platform/x86: dell-wmi-descriptor: check if memory was allocated

devm_kzalloc will return NULL pointer if no memory was allocated.
This should be checked.  This problem also existed when the driver
was dell-wmi.c.
Signed-off-by: NMario Limonciello <mario.limonciello@dell.com>
Reviewed-by: NPali Rohár <pali.rohar@gmail.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/dell-wmi-descriptor.c

@@ -121,6 +121,11 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
 	priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),
 	GFP_KERNEL);
 
+	if (!priv) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
 	priv->interface_version = buffer[2];
 	priv->size = buffer[3];
 	ret = 0;