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/kontron_sl28_defconfig b/configs/kontron_sl28_defconfig
index 3b33272..ef01452 100644
--- a/configs/kontron_sl28_defconfig
+++ b/configs/kontron_sl28_defconfig
@@ -47,7 +47,7 @@
 CONFIG_SPL_BSS_MAX_SIZE=0x100000
 CONFIG_SPL_BOARD_INIT=y
 # CONFIG_SPL_SHARES_INIT_SP_ADDR is not set
-CONFIG_SYS_SPL_MALLOC=y
+CONFIG_SPL_SYS_MALLOC=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x900
 CONFIG_SPL_MPC8XXX_INIT_DDR=y