mfd: stmfx: Nullify stmfx->vdd in case of error

Nullify stmfx->vdd in case devm_regulator_get_optional() returns an error.
And simplify code by returning an error only if return code is not -ENODEV,
which means there is no vdd regulator and it is not an issue.

Fixes: d75846e ("mfd: stmfx: Fix dev_err_probe() call in stmfx_chip_init()")
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20230609092804.793100-2-amelie.delaunay@foss.st.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: ADESTM

drivers/mfd/stmfx.c

@@ -330,9 +330,8 @@ static int stmfx_chip_init(struct i2c_client *client)
 	stmfx->vdd = devm_regulator_get_optional(&client->dev, "vdd");
 	ret = PTR_ERR_OR_ZERO(stmfx->vdd);
 	if (ret) {
-		if (ret == -ENODEV)
-			stmfx->vdd = NULL;
-		else
+		stmfx->vdd = NULL;
+		if (ret != -ENODEV)
 			return dev_err_probe(&client->dev, ret, "Failed to get VDD regulator\n");
 	}