phy: tegra: Constify static device_type structs

The only usage of tegra_xusb_pad_type and tegra_xusb_port_type is to
assign their address to the type field in the device struct, which is a
const pointer. Make them const to allow the compiler to put them in
read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20201109215844.167954-1-rikard.falkeborn@gmail.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/tegra/xusb.c

@@ -146,7 +146,7 @@ static void tegra_xusb_pad_release(struct device *dev)
 	pad->soc->ops->remove(pad);
 }
 
-static struct device_type tegra_xusb_pad_type = {
+static const struct device_type tegra_xusb_pad_type = {
 	.release = tegra_xusb_pad_release,
 };
 
@@ -513,7 +513,7 @@ static void tegra_xusb_port_release(struct device *dev)
 		port->ops->release(port);
 }
 
-static struct device_type tegra_xusb_port_type = {
+static const struct device_type tegra_xusb_port_type = {
 	.release = tegra_xusb_port_release,
 };