sh: Fix clock framework compiler warnings.

  CC      arch/sh/kernel/cpu/clock.o
  arch/sh/kernel/cpu/clock.c: In function 'clk_disable':
  arch/sh/kernel/cpu/clock.c:156: warning: 'return' with a value, in function returning void

Introduced by ("sh: enable and disable clocks recursively").
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/clock.c

@@ -153,7 +153,7 @@ void clk_disable(struct clk *clk)
 	unsigned long flags;
 
 	if (!clk)
-		return -EINVAL;
+		return;
 
 	spin_lock_irqsave(&clock_lock, flags);
 	__clk_disable(clk);