Auto merge of #117307 - taiki-e:espidf-atomic-64, r=Amanieu

Set max_atomic_width for riscv32*-esp-espidf to 32

Fixes #117305

> Since riscv32 does not have 64-bit atomic instructions, I do not believe there is any way to fix this problem other than setting max_atomic_width of these targets to 32.

This is a breaking change because Atomic\*64 will become unavailable, but all affected targets are tier 3, and the current Atomic*64 violates the standard library's API contract and can cause problems with code that rely on the standard library's atomic types being lock-free.

r? `@Amanieu`
cc `@ivmarkov` `@MabezDev`

Author: bors