malloc_simple: Add Kconfig option for using only malloc_simple in the SPL

common/dlmalloc.c is quite big, both in .text and .data usage, therefor
on some boards the SPL is build to use only malloc_simple.c and not the
dlmalloc.c code. This is done in various include/configs/foo.h with the
following construct:

 #ifdef CONFIG_SPL_BUILD
 #define CONFIG_SYS_MALLOC_SIMPLE
 #endif

This commit introduces a SPL_MALLOC_SIMPLE Kconfig bool which allows
selecting this functionality through Kconfig instead.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>

Kconfig

@@ -114,6 +114,16 @@ config SPL
 	help
 	  If you want to build SPL as well as the normal image, say Y.
 
+config SPL_SYS_MALLOC_SIMPLE
+	bool
+	depends on SPL
+	prompt "Only use malloc_simple functions in the spl"
+	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 SPL 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
 	depends on SPL
 	bool "Enable SDRAM location for SPL stack"

common/malloc_simple.c

@@ -40,7 +40,7 @@ void *memalign_simple(size_t align, size_t bytes)
 	return ptr;
 }
 
-#ifdef CONFIG_SYS_MALLOC_SIMPLE
+#if CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE)
 void *calloc(size_t nmemb, size_t elem_size)
 {
 	size_t size = nmemb * elem_size;

include/_exports.h

@@ -23,7 +23,7 @@
 	EXPORT_FUNC(dummy, void, free_hdlr, void)
 #endif
 	EXPORT_FUNC(malloc, void *, malloc, size_t)
-#ifndef CONFIG_SYS_MALLOC_SIMPLE
+#if !CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE)
 	EXPORT_FUNC(free, void, free, void *)
 #endif
 	EXPORT_FUNC(udelay, void, udelay, unsigned long)

include/exports.h

@@ -19,7 +19,7 @@ int printf(const char* fmt, ...);
 void install_hdlr(int, interrupt_handler_t, void*);
 void free_hdlr(int);
 void *malloc(size_t);
-#ifndef CONFIG_SYS_MALLOC_SIMPLE
+#if !CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE)
 void free(void*);
 #endif
 void __udelay(unsigned long);

include/malloc.h

@@ -872,7 +872,7 @@ extern Void_t*     sbrk();
 
 #else
 
-#ifdef CONFIG_SYS_MALLOC_SIMPLE
+#if CONFIG_IS_ENABLED(SYS_MALLOC_SIMPLE)
 #define malloc malloc_simple
 #define realloc realloc_simple
 #define memalign memalign_simple