OxPCIe952: Fix read8/write8 argument

This was missed in commit bde6d309 as the driver is not enabled
in any configuration by default.

Change-Id: I3d886531f5bcf013fc22ee0a1e8fa250d7c4c1a4
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/8660
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
diff --git a/src/drivers/uart/uart8250mem.c b/src/drivers/uart/uart8250mem.c
index 5fbbeec..cb70700 100644
--- a/src/drivers/uart/uart8250mem.c
+++ b/src/drivers/uart/uart8250mem.c
@@ -36,12 +36,12 @@
 
 static uint8_t uart8250_read(void *base, uint8_t reg)
 {
-	return read8((uintptr_t) (base + reg));
+	return read8(base + reg);
 }
 
 static void uart8250_write(void *base, uint8_t reg, uint8_t data)
 {
-	write8((uintptr_t) (base + reg), data);
+	write8(base + reg, data);
 }
 
 static int uart8250_mem_can_tx_byte(void *base)