counter: rz-mtu3-cnt: Unlock on error in rz_mtu3_count_ceiling_write()

These error paths need to call mutex_unlock(&priv->lock) before
returning.  The lock is taken in rz_mtu3_lock_if_counter_is_valid().

Fixes: 25d2144 ("counter: Add Renesas RZ/G2L MTU3a counter driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/7b535d6b-6031-493a-84f6-82842089e637@kili.mountain

Author: Dan Carpenter

drivers/counter/rz-mtu3-cnt.c

@@ -358,13 +358,17 @@ static int rz_mtu3_count_ceiling_write(struct counter_device *counter,
 	switch (count->id) {
 	case RZ_MTU3_16_BIT_MTU1_CH:
 	case RZ_MTU3_16_BIT_MTU2_CH:
-		if (ceiling > U16_MAX)
+		if (ceiling > U16_MAX) {
+			mutex_unlock(&priv->lock);
 			return -ERANGE;
+		}
 		priv->mtu_16bit_max[ch_id] = ceiling;
 		break;
 	case RZ_MTU3_32_BIT_CH:
-		if (ceiling > U32_MAX)
+		if (ceiling > U32_MAX) {
+			mutex_unlock(&priv->lock);
 			return -ERANGE;
+		}
 		priv->mtu_32bit_max = ceiling;
 		break;
 	default: