clk: add prototype for clk_is_enabled

On MXS we need to poll the busy bit when changing a clock rate, but only
when the parent clocks are enabled. This exposes the already present
function clk_is_enabled which is suitable for this job.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/clk/clk.c

@@ -208,7 +208,7 @@ int clk_register(struct clk *clk)
 	return 0;
 }
 
-static int clk_is_enabled(struct clk *clk)
+int clk_is_enabled(struct clk *clk)
 {
 	int enabled;
 

include/linux/clk.h

@@ -216,6 +216,7 @@ struct clk *clk_gate(const char *name, const char *parent, void __iomem *reg,
 		u8 shift);
 struct clk *clk_gate_inverted(const char *name, const char *parent, void __iomem *reg,
 		u8 shift);
+int clk_is_enabled(struct clk *clk);
 
 int clk_is_enabled_always(struct clk *clk);