phy: tegra: xusb: check return value of devm_kzalloc()

devm_kzalloc() returns a pointer to dynamically allocated memory.
Pointer could be NULL in case allocation fails. Check pointer validity.
Identified with coccinelle (kmerr.cocci script).

Fixes: f67213ce ("phy: tegra: xusb: Add usb-role-switch support")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230531073950.145339-1-claudiu.beznea@microchip.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/tegra/xusb.c

@@ -676,6 +676,9 @@ static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
 	port->dev.driver = devm_kzalloc(&port->dev,
 					sizeof(struct device_driver),
 					GFP_KERNEL);
+	if (!port->dev.driver)
+		return -ENOMEM;
+
 	port->dev.driver->owner	 = THIS_MODULE;
 
 	port->usb_role_sw = usb_role_switch_register(&port->dev,