spl: Use CONFIG_SPL... instead of CONFIG_..._SPL_...

We like to put the SPL first so it is clear that it relates to SPL. Rename
various malloc-related options which have crept in, to stick to this
convention.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/configs/wandboard_defconfig b/configs/wandboard_defconfig
index 0493ef2..7c1727f 100644
--- a/configs/wandboard_defconfig
+++ b/configs/wandboard_defconfig
@@ -33,7 +33,7 @@
 CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE=y
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_BOARD_EARLY_INIT_F=y
-CONFIG_SYS_SPL_MALLOC=y
+CONFIG_SPL_SYS_MALLOC=y
 CONFIG_SPL_FIT_IMAGE_TINY=y
 CONFIG_SPL_FS_EXT4=y
 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME="u-boot-dtb.img"