x86: Fix x86_model test in es7000_apic_is_cluster()

For the x86_model to be greater than 6 or less than 12 is
logically always true.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>