x86/fpu: Move CPUID leaf definitions to common code

Move the XSAVE-related CPUID leaf definitions to common code.  Then,
use the new definition to remove the last magic number from the CPUID
level dependency table.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/all/20241213205037.43C57CDE%40davehans-spike.ostc.intel.com