s5pc1xx: support serial driver

This patch includes the serial driver for s5pc1xx.
s5pc1xx uart driver needs own register setting and clock configuration.
So, need to special driver.

Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/include/serial.h b/include/serial.h
index 821b583..bbda3f0 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -43,6 +43,13 @@
 extern struct serial_device s3c24xx_serial2_device;
 #endif
 
+#if defined(CONFIG_S5PC1XX)
+extern struct serial_device s5pc1xx_serial0_device;
+extern struct serial_device s5pc1xx_serial1_device;
+extern struct serial_device s5pc1xx_serial2_device;
+extern struct serial_device s5pc1xx_serial3_device;
+#endif
+
 #if defined(CONFIG_OMAP3_ZOOM2)
 extern struct serial_device zoom2_serial_device0;
 extern struct serial_device zoom2_serial_device1;