MIPS: Malta: make a needlessly global integer variable static

The variable `mips_revision_corid' is needlessly defined global in
arch/mips/mti-malta/malta-init.c, and this patch makes it static.

Build-tested with malta_defconfig.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mti-malta/malta-init.c b/arch/mips/mti-malta/malta-init.c
index 4832af2..475038a 100644
--- a/arch/mips/mti-malta/malta-init.c
+++ b/arch/mips/mti-malta/malta-init.c
@@ -48,7 +48,7 @@
 
 int init_debug = 0;
 
-int mips_revision_corid;
+static int mips_revision_corid;
 int mips_revision_sconid;
 
 /* Bonito64 system controller register base. */