cpufreq: exynos: Add missing static

Add missing 'static' qualifiers.

Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/drivers/cpufreq/exynos5250-cpufreq.c b/drivers/cpufreq/exynos5250-cpufreq.c
index 736a5cf..b934486 100644
--- a/drivers/cpufreq/exynos5250-cpufreq.c
+++ b/drivers/cpufreq/exynos5250-cpufreq.c
@@ -143,7 +143,7 @@
 
 }
 
-bool exynos5250_pms_change(unsigned int old_index, unsigned int new_index)
+static bool exynos5250_pms_change(unsigned int old_index, unsigned int new_index)
 {
 	unsigned int old_pm = apll_freq_5250[old_index].mps >> 8;
 	unsigned int new_pm = apll_freq_5250[new_index].mps >> 8;