x86/cpu: Introduce and use CPUID leaf 0x2 parsing helpers

x86/cpu: Introduce and use CPUID leaf 0x2 parsing helpers

Introduce CPUID leaf 0x2 parsing helpers at <asm/cpuid/leaf_0x2_api.h>.
This allows sharing the leaf 0x2's output validation and iteration logic
across both x86/cpu intel.c and cacheinfo.c.

Start by converting intel.c to the new API.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250324133324.23458-4-darwi@linutronix.de