PCIe support & virtio PCIe driver

[EDGW]

This PR includes

• the enumeration, initialization and probe logic of multi-level buses for PCIe devices,
• the PCIe driver for virtio devices, and
• the interrupt mapping mechanism.

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[Copilot]

Pull request overview

Adds initial PCIe support to the kernel, including multi-level PCIe bus enumeration, PCIe virtio transport, BAR pre-initialization/mapping, and DT-based interrupt-map parsing for the root bus (with platform/QEMU config updates for LoongArch64).

Changes:

• Introduce PCIe bus infrastructure (ECAM access, device/domain modeling, address parsing, BAR sizing/allocation, and ioremap registry).
• Add a VirtIO PCIe transport driver and update VirtIO HAL/device IRQ wiring for PCIe-backed virtio devices.
• Implement DT ranges + interrupt-map parsing for the PCIe host bridge and update LoongArch64 QEMU platform/rootfs configs.

Reviewed changes

Copilot reviewed 26 out of 27 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
conf/rootfs/minimal.toml	Switches minimal rootfs build arch to loongarch64.
conf/platforms/qemu-virt-la64.toml	Enables virtio-blk PCIe devices and sets rootfs settings for LoongArch64 QEMU.
anemone-kernel/src/mm/remap.rs	Exposes IoRemap virtual base and size for PCIe/ioremap consumers.
anemone-kernel/src/exception/intr/irq.rs	Adds IrqDomain::xlate helper to translate interrupt specifiers.
anemone-kernel/src/driver/virtio/pcie.rs	New VirtIO PCIe transport driver (virtio-drivers PciTransport integration).
anemone-kernel/src/driver/virtio/mod.rs	Implements mmio_phys_to_virt using the PCIe remap registry.
anemone-kernel/src/driver/pcie_drivers/platform.rs	PCIe ECAM platform driver: parses DT bus-range, ranges, and interrupt-map.
anemone-kernel/src/driver/pcie_drivers/bus.rs	Bridge driver: multi-level bus enumeration, BAR/bridge window setup, interrupt keying.
anemone-kernel/src/driver/intc/sifive_plic.rs	Makes PLIC xlate unconditional on OF-node presence (supports non-OF fw nodes).
anemone-kernel/src/driver/intc/loongson_platic.rs	Same xlate behavior adjustment for LA7A1000 PLATIC.
anemone-kernel/src/driver/block/virtio_blk.rs	Requests IRQ earlier during virtio-blk probe.
anemone-kernel/src/device/bus/virtio/device.rs	Allows virtio transport parent to be either PlatformDevice or PcieDevice.
anemone-kernel/src/device/bus/pcie/remap.rs	New global remap registry for mapping phys MMIO ranges to virt addresses.
anemone-kernel/src/device/bus/pcie/mod.rs	PCIe module exports, naming docs, and class-code constants.
anemone-kernel/src/device/bus/pcie/fwnode.rs	New firmware-node wrapper for PCIe devices to provide interrupt routing info.
anemone-kernel/src/device/bus/pcie/ecam.rs	Enhances ECAM config access: writers, BAR/capability handling, multi-function iteration.
anemone-kernel/src/device/bus/pcie/driver.rs	Extends PCIe driver trait with vendor/device match table + postinit hook.
anemone-kernel/src/device/bus/pcie/device.rs	PCIe device/domain model, BAR resource allocators, and driver preinit/postinit flow.
anemone-kernel/src/device/bus/pcie/bus.rs	PCIe BusType: matching logic, BAR preinit/allocation/ioremap integration.
anemone-kernel/src/device/bus/pcie/addr.rs	New OpenFirmware PCI address parsing/encoding helpers.
anemone-kernel/crates/range-allocator/src/lib.rs	Adds aligned allocation and introduces IncreasingRangeAllocator; updates Rangable bounds.
anemone-kernel/crates/range-allocator/src/increasing.rs	New monotonic range allocator implementation + tests.
anemone-kernel/crates/device-tree/src/unflattened.rs	Adds raw accessors and optional address/size-cells getters.
anemone-kernel/Cargo.toml	Adds wavltree dependency.
Cargo.lock	Locks wavltree crate.
.vscode/settings.json	Switches rust-analyzer target to loongarch64.
.gitattributes	Marks PCI ID database file as binary for git attributes.

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