[MIPS] Make gcmp_probe() static
The gcmp_probe() function is needlessly defined global, and
this patch makes it static.
Tested by booting a Malta 4Kc board up to the shell prompt.
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.fi>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>