regulator: da9062: Return REGULATOR_MODE_INVALID for invalid mode

-EINVAL is not a valid return value for .of_map_mode, return
REGULATOR_MODE_INVALID instead.

Fixes: 844e7492 ("regulator: da9062: add of_map_mode support for bucks")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20191122045154.802-1-axel.lin@ingics.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/da9062-regulator.c

@@ -108,7 +108,7 @@ static unsigned int da9062_map_buck_mode(unsigned int mode)
 	case DA9063_BUCK_MODE_AUTO:
 		return REGULATOR_MODE_NORMAL;
 	default:
-		return -EINVAL;
+		return REGULATOR_MODE_INVALID;
 	}
 }