Add uartmem_init prototype.

The oxpcie ramstage code calls uartmem_init after the PCI memory
allocation, but hte function was static and didn't have a prototype.

Change-Id: Iabc1a3d248aeaed29aaaa22504defac97c572326
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/1285
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/console/uart8250mem_console.c

@@ -23,7 +23,7 @@
 
 static u32 uart_bar = 0;
 
-static void uartmem_init(void)
+void uartmem_init(void)
 {
 	uart_bar = uart_mem_init();
 }

src/include/uart8250.h

@@ -125,6 +125,7 @@ void uart8250_tx_flush(unsigned base_port);
  */
 void uart8250_init(unsigned base_port, unsigned divisor);
 void uart_init(void);
+void uartmem_init(void);
 
 /* and the same for memory mapped uarts */
 unsigned char uart8250_mem_rx_byte(unsigned base_port);