x86: Adjust section annotations in AMD Fam10 MMCONF enabling code

check_enable_amd_mmconf_dmi() gets called only for the BSP,
hence everything hanging off of it can be __init*.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CD2DE1E0200007800020990@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>