i2c-designware: use usleep_range() in the busy-loop

This is not an atomic context so there is no need to use mdelay() but
instead use usleep_range().

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 5cc4ebf..7c10c5b 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -355,7 +355,7 @@
 			return -ETIMEDOUT;
 		}
 		timeout--;
-		mdelay(1);
+		usleep_range(1000, 1100);
 	}
 
 	return 0;