ARM: S3C24XX: Make 'clk_msysclk' static

Fixes the following warning:
arch/arm/mach-s3c24xx/common-s3c2443.c:135:19: warning:
symbol 'clk_msysclk' was not declared. Should it be static?
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-s3c24xx/common-s3c2443.c

@@ -132,7 +132,7 @@ static struct clk *clk_msysclk_sources[] = {
 	[3] = &clk_mpllref,
 };
 
-struct clksrc_clk clk_msysclk = {
+static struct clksrc_clk clk_msysclk = {
 	.clk	= {
 		.name		= "msysclk",
 		.parent		= &clk_xtal,