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/common/spl/Kconfig.nxp b/common/spl/Kconfig.nxp
index fc696cf..53e9b9f 100644
--- a/common/spl/Kconfig.nxp
+++ b/common/spl/Kconfig.nxp
@@ -59,7 +59,7 @@
 config SPL_RELOC_STACK
 	hex "Address of the start of the stack SPL will use after relocation."
 	help
-	  If unspecified, this is equal to CFG_SYS_SPL_MALLOC_START.  Starting
+	  If unspecified, this is equal to CFG_SPL_SYS_MALLOC_START.  Starting
 	  address of the malloc pool used in SPL.  When this option is set the full
 	  malloc is used in SPL and it is set up by spl_init() and before that, the
 	  simple malloc() can be used if CONFIG_SYS_MALLOC_F is defined.