platform: simplify setting CORE_COUNT and MAX_CORE_COUNT

All normal SOF builds use Zephyr build system, so common settings
like system core count can be simply set based on Zephyr build options.

There are a few speciality builds left to build SOF without Zephyr.
Testbench, cmocka and the SOF ALSA plugin are a few such examples.
To keep these builds functional, add a simple definition of key
Zephyr definitions (like in this case MP_MAX_NUM_CPUS) to allow these
builds to use common build rules even when Zephyr definitions are not
available.

The old arch/host/Kconfig is removed. It is no longer needed and caused
confusion as it added a unconditional default to CORE_COUNT that was
used (more or less unintentionally) by some of the speciality build
targets.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

src/arch/host/Kconfig

@@ -332,21 +332,30 @@ config MT8196
 
 endchoice
 
-config MAX_CORE_COUNT
+#
+# For non-Zephyr builds like testbench, cmocka and SOF ALSA plugin,
+# set core count separately.
+#
+if !ZEPHYR_SOF_MODULE
+
+config MP_MAX_NUM_CPUS
 	int
-	default 5 if LUNARLAKE || PANTHERLAKE
-	default 4 if TIGERLAKE || NOVALAKE
-	default 3 if METEORLAKE
-	default 3 if WILDCATLAKE
 	default 1
 	help
 	  Maximum number of cores per configuration
 
+endif # !ZEPHYR_SOF_MODULE
+
+config MAX_CORE_COUNT
+	int
+	default MP_MAX_NUM_CPUS
+	help
+	  Maximum number of cores per configuration
+
 config CORE_COUNT
 	int "Number of cores"
-	default MP_MAX_NUM_CPUS if KERNEL_BIN_NAME = "zephyr"
-	default MAX_CORE_COUNT
-	range 1 MAX_CORE_COUNT
+	default MP_MAX_NUM_CPUS
+	range 1 MP_MAX_NUM_CPUS
 	help
 	  Number of used cores
 	  Lowering available core count could result in lower power consumption