Standardize mem_malloc_init() implementation

This lays the groundwork to allow architectures to share a common
mem_malloc_init().

Note that the x86 implementation was not modified as it did not fit the
mold of all other architectures.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/lib_nios/board.c b/lib_nios/board.c
index 30cdb47..745e0a4 100644
--- a/lib_nios/board.c
+++ b/lib_nios/board.c
@@ -55,14 +55,13 @@
 /*
  * The Malloc area is immediately below the monitor copy in RAM
  */
-static void mem_malloc_init (void)
+static void mem_malloc_init(ulong start, ulong size)
 {
-	mem_malloc_start = CONFIG_SYS_MALLOC_BASE;
-	mem_malloc_end = mem_malloc_start + CONFIG_SYS_MALLOC_LEN;
-	mem_malloc_brk = mem_malloc_start;
-	memset ((void *) mem_malloc_start,
-		0,
-		mem_malloc_end - mem_malloc_start);
+	mem_malloc_start = start;
+	mem_malloc_end = start + size;
+	mem_malloc_brk = start;
+
+	memset ((void *)mem_malloc_start, 0, size);
 }
 
 
@@ -125,7 +124,7 @@
 	}
 
 	WATCHDOG_RESET ();
-	mem_malloc_init();
+	mem_malloc_init(CONFIG_SYS_MALLOC_BASE, CONFIG_SYS_MALLOC_LEN);
 	malloc_bin_reloc();
 
 	WATCHDOG_RESET ();