net: marvell: fix a missing check of acpi_match_device

When acpi_match_device fails, its return value is NULL. Directly using
the return value without a check may result in a NULL-pointer
dereference. The fix checks if acpi_match_device fails, and if so,
returns -EINVAL.

Signed-off-by: Kangjie Lu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

···
 	if (has_acpi_companion(&pdev->dev)) {
 		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
 					    &pdev->dev);
+		if (!acpi_id)
+			return -EINVAL;
 		priv->hw_version = (unsigned long)acpi_id->driver_data;
 	} else {
 		priv->hw_version =