uart: Prepare to support multiple base addresses

Prepare low-level register access to take UART base address as a
parameter. This is done to support a list of base addresses defined
in the platform.

Change-Id: Ie630e55f2562f099b0ba9eb94b08c92d26dfdf2e
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5309
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/include/console/uart.h

@@ -48,6 +48,13 @@ int uart_can_rx_byte(void);
 unsigned int uart_platform_base(int idx);
 uint32_t uartmem_getbaseaddr(void);
 
+#if !defined(__ROMCC__)
+static inline void *uart_platform_baseptr(int idx)
+{
+	return (void *)uart_platform_base(idx);
+}
+#endif
+
 void oxford_init(void);
 void oxford_remap(unsigned int new_base);