cpu/intel/common: Move intel_ht_sibling() to common folder

Make intel_ht_sibling() available on all platforms.

Will be used in MP init to only write "Core" MSRs from one thread
on HyperThreading enabled platforms, to prevent race conditions and
resulting #GP if MSRs are written twice or are already locked.

Change-Id: I5d000b34ba4c6536dc866fbaf106b78e905e3e35
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35619
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/x86/include/arch/cpu.h

@@ -158,6 +158,7 @@ static inline unsigned int cpuid_edx(unsigned int op)
 
 #define CPUID_FEATURE_PAE (1 << 6)
 #define CPUID_FEATURE_PSE36 (1 << 17)
+#define CPUID_FEAURE_HTT (1 << 28)
 
 // Intel leaf 0x4, AMD leaf 0x8000001d EAX