x86: Add new Intel CPU cache size descriptors

The latest rev of Intel doc AP-485 details new cache descriptors
that we don't yet support. 12MB, 18MB and 24MB 24-way assoc L3
caches.

Signed-off-by: Dave Jones <davej@redhat.com>
LKML-Reference: <20091110184924.GA20337@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>