sa1100: move serial driver to drivers/serial

add CONFIG_SA1100_SERIAL to activate the driver

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/include/configs/gcplus.h b/include/configs/gcplus.h
index 81ee05f..77d4578 100644
--- a/include/configs/gcplus.h
+++ b/include/configs/gcplus.h
@@ -70,6 +70,7 @@
 /*
  * select serial console configuration
  */
+#define CONFIG_SA1100_SERIAL
 #define CONFIG_SERIAL3          1	/* we use SERIAL 3 on ADS GCPlus */
 
 /* allow to overwrite serial and ethaddr */