Input: mtk-pmic-keys: Fix null pointer dereference when no compatible data

In mtk_pmic_keys_probe function, the of_match_device function is
called to retrieve the compatible platform device info but its return
data pointer is not checked. It can lead to a null pointer deference
later when accessing the data field, if of_match_device returned a null
pointer. So, add a pointer check after calling of_match_device function
and return an EINVAL error in null case.

Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>

drivers/input/keyboard/mtk-pmic-keys.c

@@ -345,6 +345,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
 	const struct of_device_id *of_id =
 		of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
 
+	if (!of_id)
+		return -EINVAL;
+
 	keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
 	if (!keys)
 		return -ENOMEM;