mfd: twl6040: Check clk_prepare_enable() return value in twl6040_power()

The clk_prepare_enable() function can fail so check the return
value and propagate the error in case of a failure.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/twl6040.c

@@ -291,7 +291,11 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 		if (twl6040->power_count++)
 			goto out;
 
-		clk_prepare_enable(twl6040->clk32k);
+		ret = clk_prepare_enable(twl6040->clk32k);
+		if (ret) {
+			twl6040->power_count = 0;
+			goto out;
+		}
 
 		/* Allow writes to the chip */
 		regcache_cache_only(twl6040->regmap, false);