x86-32, NUMA: Move get_memcfg_numa() into numa_32.c

There's no reason get_memcfg_numa() to be implemented inline in
mmzone_32.h.  Move it to numa_32.c and also make
get_memcfg_numa_flag() static.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>