x86/cpuid: Rename cpuid_leaf()/cpuid_subleaf() APIs

x86/cpuid: Rename cpuid_leaf()/cpuid_subleaf() APIs

A new CPUID model will be added where its APIs will be designated as the
official CPUID API.  Free the cpuid_leaf() and cpuid_subleaf() function
names for that API.  Rename them accordingly to cpuid_read() and
cpuid_read_subleaf().

For kernel/cpuid.c, rename its local file operations read function from
cpuid_read() to cpuid_read_f() so that it does not conflict with the new
API.

No functional change.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20260327021645.555257-1-darwi@linutronix.de