serial: Rename SERIAL_SUPPORT to SERIAL

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/evb-ast2600_defconfig b/configs/evb-ast2600_defconfig
index b79e4a8..56ab885 100644
--- a/configs/evb-ast2600_defconfig
+++ b/configs/evb-ast2600_defconfig
@@ -11,7 +11,7 @@
 CONFIG_ENV_SIZE=0x10000
 CONFIG_SYS_MALLOC_LEN=0x2000000
 CONFIG_DEFAULT_DEVICE_TREE="ast2600-evb"
-CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_SPL_SERIAL=y
 CONFIG_SPL_SIZE_LIMIT=0x10000
 CONFIG_SPL=y
 # CONFIG_ARMV7_NONSEC is not set