x86: fix MP_processor_info section mismatch warning

WARNING: arch/x86/kernel/built-in.o(.cpuinit.text+0x1fe7): Section mismatch in reference from the function MP_processor_info() to the variable .init.data:x86_quirks
The function __cpuinit MP_processor_info() references
a variable __initdata x86_quirks.
If x86_quirks is only used by MP_processor_info then
annotate x86_quirks with a matching annotation.

MP_processor_info uses x86_quirks which is __init and is used only from
smp_read_mpc and construct_default_ISA_mptable which are __init

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>