x86, cpu: Make APERF/MPERF a normal table-driven flag

APERF/MPERF can be handled via the table like all the other scattered
CPU flags.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1270065406-1814-4-git-send-email-bp@amd64.org>