ppc: Rename MPC8XXX_INIT_DDR_SUPPORT to MPC8XXX_INIT_DDR

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/ls1043ardb_nand_SECURE_BOOT_defconfig b/configs/ls1043ardb_nand_SECURE_BOOT_defconfig
index 07f35c1..6a11a7c 100644
--- a/configs/ls1043ardb_nand_SECURE_BOOT_defconfig
+++ b/configs/ls1043ardb_nand_SECURE_BOOT_defconfig
@@ -33,7 +33,7 @@
 CONFIG_SPL_CRYPTO=y
 CONFIG_SPL_HASH_SUPPORT=y
 CONFIG_SPL_ENV_SUPPORT=y
-CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT=y
+CONFIG_SPL_MPC8XXX_INIT_DDR=y
 CONFIG_SPL_NAND_SUPPORT=y
 CONFIG_SPL_WATCHDOG=y
 CONFIG_CMD_IMLS=y