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/common/spl/Kconfig b/common/spl/Kconfig
index 533ec90..76bb294 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -742,7 +742,7 @@
 	  Enable write access to MMC and SD Cards in SPL
 
 
-config SPL_MPC8XXX_INIT_DDR_SUPPORT
+config SPL_MPC8XXX_INIT_DDR
 	bool "Support MPC8XXX DDR init"
 	help
 	  Enable support for DDR-SDRAM (double-data-rate synchronous dynamic
@@ -1509,11 +1509,11 @@
 	  Enable support for generic U-Boot libraries within TPL. See
 	  SPL_LIBGENERIC_SUPPORT for details.
 
-config TPL_MPC8XXX_INIT_DDR_SUPPORT
+config TPL_MPC8XXX_INIT_DDR
 	bool "Support MPC8XXX DDR init"
 	help
 	  Enable support for DDR-SDRAM on the MPC8XXX family within TPL. See
-	  SPL_MPC8XXX_INIT_DDR_SUPPORT for details.
+	  SPL_MPC8XXX_INIT_DDR for details.
 
 config TPL_MMC
 	bool "Support MMC"