x86/microcode: Consolidate family,model, ... code

... to the header. Split the family acquiring function into a
main one, doing CPUID and a helper which computes the extended
family and is used in multiple places. Get rid of the locally-grown
get_x86_{family,model}().

While at it, rename local variables to something more descriptive and
vertically align assignments for better readability.

There should be no functionality change resulting from this patch.

Signed-off-by: Borislav Petkov <bp@suse.de>

diff --cc arch/x86/include/asm/microcode.h
Simple merge

diff --cc arch/x86/kernel/cpu/microcode/core_early.c
Simple merge

diff --cc arch/x86/kernel/cpu/microcode/intel_early.c
Simple merge