drivers/uart/oxpcie.c: Get rid of device_t

Use of `device_t` has been abandoned in ramstage.

Change-Id: If2b9cbf130f963bc1bedef16b7951e9546054743
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26012
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/drivers/uart/oxpcie.c

@@ -21,7 +21,7 @@
 #include <console/uart.h>
 #include <arch/io.h>
 
-static void oxford_oxpcie_enable(device_t dev)
+static void oxford_oxpcie_enable(struct device *dev)
 {
 	printk(BIOS_DEBUG, "Initializing Oxford OXPCIe952\n");