clk: u300: Silence sparse warnings

drivers/clk/clk-u300.c:1175:13: warning: symbol 'u300_clk_init' was not declared. Should it be static?
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-u300.c

@@ -12,6 +12,7 @@
 #include <linux/clk-provider.h>
 #include <linux/spinlock.h>
 #include <linux/of.h>
+#include <linux/platform_data/clk-u300.h>
 
 /* APP side SYSCON registers */
 /* CLK Control Register 16bit (R/W) */