leds: lp3944: Fix return value

Return the value obtained from i2c_smbus_read_byte_data() instead of
-EINVAL. Silences the following smatch warning:
drivers/leds/leds-lp3944.c:89 lp3944_reg_read() info:
why not propagate 'tmp' from i2c_smbus_read_byte_data() instead of -22?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
diff --git a/drivers/leds/leds-lp3944.c b/drivers/leds/leds-lp3944.c
index c298f7d..b2d82e2 100644
--- a/drivers/leds/leds-lp3944.c
+++ b/drivers/leds/leds-lp3944.c
@@ -86,7 +86,7 @@
 
 	tmp = i2c_smbus_read_byte_data(client, reg);
 	if (tmp < 0)
-		return -EINVAL;
+		return tmp;
 
 	*value = tmp;