sh: Implement clk_round_rate() in the clock framework.

This is an optional component of the clock framework. However,
as we're going to be using this in the cpufreq drivers, add
support for it to the framework.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/asm-sh/clock.h

@@ -14,6 +14,7 @@ struct clk_ops {
 	void (*disable)(struct clk *clk);
 	void (*recalc)(struct clk *clk);
 	int (*set_rate)(struct clk *clk, unsigned long rate, int algo_id);
+	long (*round_rate)(struct clk *clk, unsigned long rate);
 };
 
 struct clk {