regulator: da9063: Simplify da9063_buck_set_mode for BUCK_MODE_MANUAL case

The sleep flag bit decides the mode for BUCK_MODE_MANUAL case, simplify
the logic as the result is the same.

Signed-off-by: Axel Lin <[e-mail]>
Reviewed-by: Adam Thomson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/da9063-regulator.c

···
 {
 	struct da9063_regulator *regl = rdev_get_drvdata(rdev);
 	struct regmap_field *field;
-	unsigned int val, mode = 0;
+	unsigned int val;
 	int ret;
 
 	ret = regmap_field_read(regl->mode, &val);
···
 	switch (val) {
 	default:
 	case BUCK_MODE_MANUAL:
-		mode = REGULATOR_MODE_FAST | REGULATOR_MODE_STANDBY;
 		/* Sleep flag bit decides the mode */
 		break;
 	case BUCK_MODE_SLEEP:
···
 		return 0;
 
 	if (val)
-		mode &= REGULATOR_MODE_STANDBY;
+		return REGULATOR_MODE_STANDBY;
 	else
-		mode &= REGULATOR_MODE_NORMAL | REGULATOR_MODE_FAST;
-
-	return mode;
+		return REGULATOR_MODE_FAST;
 }
 
 /*