clk: emev2: Silence sparse warnings

drivers/clk/shmobile/clk-emev2.c:37:14: warning: symbol 'smu_base' was not declared. Should it be static?

Cc: Takashi Yoshii <takasi-y@ops.dti.ne.jp>
Cc: Magnus Damm <damm@opensource.se>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/shmobile/clk-emev2.c

@@ -34,7 +34,7 @@
 static DEFINE_SPINLOCK(lock);
 
 /* not pretty, but hey */
-void __iomem *smu_base;
+static void __iomem *smu_base;
 
 static void __init emev2_smu_write(unsigned long value, int offs)
 {