x86, cacheinfo: Make L3 cache info per node

Currently, we're allocating L3 cache info and calculating indices for
each online cpu which is clearly superfluous. Instead, we need to do
this per-node as is each L3 cache.

No functional change, only per-cpu memory savings.

-v2: Allocate L3 cache descriptors array dynamically.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1271945222-5283-5-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>