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/am335x_evm_defconfig b/configs/am335x_evm_defconfig
index d7cf7d7..f048e60 100644
--- a/configs/am335x_evm_defconfig
+++ b/configs/am335x_evm_defconfig
@@ -20,8 +20,8 @@
 CONFIG_LOGLEVEL=3
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_ARCH_MISC_INIT=y
-CONFIG_SYS_SPL_MALLOC=y
-CONFIG_SYS_SPL_MALLOC_SIZE=0x800000
+CONFIG_SPL_SYS_MALLOC=y
+CONFIG_SPL_SYS_MALLOC_SIZE=0x800000
 CONFIG_SPL_FIT_IMAGE_TINY=y
 CONFIG_SPL_ETH=y
 # CONFIG_SPL_FS_EXT4 is not set