clk: ux500: add range to usleep_range

Providing a range for usleep_range() allows the hrtimer subsystem to
coalesce timers - the delay is runtime configurable so a factor 2
is taken to provide the range. With the expected range for
enable_delay_us being milliseconds, the range should lie in the 250us
range which is sufficient for hrtimer optimization.

Signed-off-by: Nicholas Mc Guire <hofrat@opentech.at>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/ux500/clk-sysctrl.c

@@ -42,7 +42,8 @@ static int clk_sysctrl_prepare(struct clk_hw *hw)
 				clk->reg_bits[0]);
 
 	if (!ret && clk->enable_delay_us)
-		usleep_range(clk->enable_delay_us, clk->enable_delay_us);
+		usleep_range(clk->enable_delay_us, clk->enable_delay_us +
+			     (clk->enable_delay_us >> 2));
 
 	return ret;
 }