Blackfin: uart: add multiple serial support

This brings CONFIG_SERIAL_MULTI support to the Blackfin on-chip UARTs.
Ends up adding only ~512bytes per additional UART.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/serial.h b/include/serial.h
index f21d961..4aa1cdc 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -71,6 +71,15 @@
 extern struct serial_device serial_btuart_device;
 extern struct serial_device serial_stuart_device;
 
+#if defined(CONFIG_SYS_BFIN_UART)
+extern void serial_register_bfin_uart(void);
+extern struct serial_device bfin_serial0_device;
+extern struct serial_device bfin_serial1_device;
+extern struct serial_device bfin_serial2_device;
+extern struct serial_device bfin_serial3_device;
+#endif
+
+extern void serial_register(struct serial_device *);
 extern void serial_initialize(void);
 extern void serial_stdio_init(void);
 extern int serial_assign(char * name);