ASoC: wm_adsp: Use usleep_range for short delay

Replace the 1ms msleep in wm_adsp2_ena with a usleep_range, as per
normal guidance on delay functions. Also tighten up the delay a little
as 1ms was quite generous.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm_adsp.c

@@ -2237,7 +2237,7 @@ static int wm_adsp2_ena(struct wm_adsp *dsp)
 		if (val & ADSP2_RAM_RDY)
 			break;
 
-		msleep(1);
+		usleep_range(250, 500);
 	}
 
 	if (!(val & ADSP2_RAM_RDY)) {