x86/cacheinfo: Extract out cache level topology ID calculation

For Intel CPUID leaf 0x4 parsing, refactor the cache level topology ID
calculation code into its own method instead of repeating the same logic
twice for L2 and L3.

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/20250324133324.23458-26-darwi@linutronix.de