mfd: da903x: Simplify function return logic

The invoked function already returns zero on success or a negative
errno code so there is no need to open code the logic in the caller.

Signed-off-by: Javier Martinez Canillas <[e-mail]>
Acked-by: Adam Thomson <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/da903x.c

···
 		return ret;
 	}
 
-	ret = da903x_add_subdevs(chip, pdata);
-	if (ret)
-		return ret;
-
-	return 0;
+	return da903x_add_subdevs(chip, pdata);
 }
 
 static int da903x_remove(struct i2c_client *client)