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/uniphier_v7_defconfig b/configs/uniphier_v7_defconfig
index d848863..19701c2 100644
--- a/configs/uniphier_v7_defconfig
+++ b/configs/uniphier_v7_defconfig
@@ -7,7 +7,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="uniphier-pxs2-vodka"
 CONFIG_SPL_TEXT_BASE=0x00100000
 CONFIG_SPL_MMC=y
-CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_SPL_SERIAL=y
 CONFIG_SPL=y
 CONFIG_MICRO_SUPPORT_CARD=y
 CONFIG_SYS_LOAD_ADDR=0x85000000