ARM: Add function to get clock usecount

Adds function to get clock usecount.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/asm-arm/hardware/clock.h

@@ -66,6 +66,12 @@ int clk_use(struct clk *clk);
  */
 void clk_unuse(struct clk *clk);
 
+/**
+ * clk_get_usecount - get the use count
+ * @clk: clock source
+ */
+int clk_get_usecount(struct clk *clk);
+
 /**
  * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
  *		  This is only valid once the clock source has been enabled.