soc: xtensa: intel_adsp: HWMv2 workaround for SOF config

Apply a workaround at Kconfig.defconfig for CORE_COUNT default
value set overriding SOF arch/host incorrect defaults chosen
without ARCH specified by the changed HWMv2 cmake sequence.

Signed-off-by: Dmitrii Golovanov <dmitrii.golovanov@intel.com>