m68k: coldfire: make symbol m523x_clk_lookup static

Fix sparse warnings:

arch/m68k/coldfire/m523x.c:31:19: sparse: sparse: symbol 'm523x_clk_lookup' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Jingjin <wangjingjin1@huawei.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

arch/m68k/coldfire/m523x.c

@@ -28,7 +28,7 @@
 DEFINE_CLK(pll, "pll.0", MCF_CLK);
 DEFINE_CLK(sys, "sys.0", MCF_BUSCLK);
 
-struct clk_lookup m523x_clk_lookup[] = {
+static struct clk_lookup m523x_clk_lookup[] = {
 	CLKDEV_INIT(NULL, "pll.0", &clk_pll),
 	CLKDEV_INIT(NULL, "sys.0", &clk_sys),
 	CLKDEV_INIT("mcfpit.0", NULL, &clk_pll),