malloc: remove !gd handling

Following the previous patch, malloc() is never called before gd is set,
so we can remove the special-case check for this condition.

This reverts commit 854d2b9753e4 "dlmalloc: ensure gd is set for early
alloc".

Cc: Rabin Vincent <rabin@rab.in>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

common/dlmalloc.c

@@ -2184,7 +2184,7 @@ Void_t* mALLOc(bytes) size_t bytes;
   INTERNAL_SIZE_T nb;
 
 #ifdef CONFIG_SYS_MALLOC_F_LEN
-	if (gd && !(gd->flags & GD_FLG_FULL_MALLOC_INIT))
+	if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT))
 		return malloc_simple(bytes);
 #endif