x86: fix section mismatch in setup_64.c:srat_detect_node

srat_detect_node() is only used by __cpuinit init_intel().
So the trivial fix is to annotate srat_detect_node() with __cpuinit.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>