spl: Kconfig: split SYS_MALLOC_SIMPLE for TPL and SPL

As include/malloc.h already checks for SYS_MALLOC_SIMPLE using the
CONFIG_IS_ENABLED macro, we need to move to having separate entries
as we switch to fully separate configuration for SPL and TPL.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/spl/Kconfig

@@ -62,6 +62,15 @@ config SPL_SYS_MALLOC_SIMPLE
 	  this will make the SPL binary smaller at the cost of more heap
 	  usage as the *_simple malloc functions do not re-use free-ed mem.
 
+config TPL_SYS_MALLOC_SIMPLE
+	bool
+	prompt "Only use malloc_simple functions in the TPL"
+	help
+	  Say Y here to only use the *_simple malloc functions from
+	  malloc_simple.c, rather then using the versions from dlmalloc.c;
+	  this will make the TPL binary smaller at the cost of more heap
+	  usage as the *_simple malloc functions do not re-use free-ed mem.
+
 config SPL_STACK_R
 	bool "Enable SDRAM location for SPL stack"
 	help