drm/vc4: Replace long HDMI udelay with usleep_range

Since we aren't in atomic context replace this long udelay with a
usleep_range.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NEric Anholt <eric@anholt.net>
Reviewed-by: NEric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1519475894-11701-1-git-send-email-stefan.wahren@i2se.com

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -681,7 +681,7 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
 			   drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
 		HDMI_WRITE(VC4_HDMI_FIFO_CTL,
 			   drift | VC4_HDMI_FIFO_CTL_RECENTER);
-		udelay(1000);
+		usleep_range(1000, 1100);
 		HDMI_WRITE(VC4_HDMI_FIFO_CTL,
 			   drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
 		HDMI_WRITE(VC4_HDMI_FIFO_CTL,