x86, cacheinfo: Reorganize AMD L3 cache structure

Add a struct representing L3 cache attributes (subcache sizes and
indices count) and move the respective members out of _cpuid4_info.
Also, stash the struct pci_dev ptr into the struct simplifying the code
even more.

There should be no functionality change resulting from this patch except
slightly slimming the _cpuid4_info per-cpu vars.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1271945222-5283-4-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>