serial: Support serial multi for Microblaze

enable serial multi for Microblaze.

Signed-off-by: Michal Simek <monstr@monstr.eu>
Acked-by: Stephan Linz <linz@li-pro.net>
diff --git a/include/serial.h b/include/serial.h
index cbdf8a9..d76d6df 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -31,7 +31,8 @@
 	defined(CONFIG_MB86R0x) || defined(CONFIG_MPC5xxx) || \
 	defined(CONFIG_MPC83xx) || defined(CONFIG_MPC85xx) || \
 	defined(CONFIG_MPC86xx) || defined(CONFIG_SYS_SC520) || \
-	defined(CONFIG_TEGRA20) || defined(CONFIG_SYS_COREBOOT)
+	defined(CONFIG_TEGRA20) || defined(CONFIG_SYS_COREBOOT) || \
+	defined(CONFIG_MICROBLAZE)
 extern struct serial_device serial0_device;
 extern struct serial_device serial1_device;
 #if defined(CONFIG_SYS_NS16550_SERIAL)