common: Tidy up how malloc() is inited

The call to malloc() is a bit strange. The naming of the arguments
suggests that an address is passed, but in fact it is a pointer, at
least in the board_init_r() function and SPL equivalent.

Update it to work as described. Add a function comment as well.

Note that this does adjustment does not extend into the malloc()
implementation itself, apart from changing mem_malloc_init(), since
there are lots of casts and pointers and integers are used
interchangeably.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

common/dlmalloc.c

@@ -16,6 +16,8 @@
 #include <asm/global_data.h>
 
 #include <malloc.h>
+#include <mapmem.h>
+#include <string.h>
 #include <asm/io.h>
 #include <valgrind/memcheck.h>
 
@@ -598,9 +600,9 @@ void *sbrk(ptrdiff_t increment)
 
 void mem_malloc_init(ulong start, ulong size)
 {
-	mem_malloc_start = start;
-	mem_malloc_end = start + size;
-	mem_malloc_brk = start;
+	mem_malloc_start = (ulong)map_sysmem(start, size);
+	mem_malloc_end = mem_malloc_start + size;
+	mem_malloc_brk = mem_malloc_start;
 
 #ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
 	malloc_init();