regulator: mt6315: Return REGULATOR_MODE_INVALID for invalid mode

-EINVAL is not a valid return value for .of_map_mode, return
REGULATOR_MODE_INVALID instead.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20210215034813.45510-1-axel.lin@ingics.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/mt6315-regulator.c

@@ -69,7 +69,7 @@ static unsigned int mt6315_map_mode(u32 mode)
 	case MT6315_BUCK_MODE_LP:
 		return REGULATOR_MODE_IDLE;
 	default:
-		return -EINVAL;
+		return REGULATOR_MODE_INVALID;
 	}
 }