cmd_fdt: Actually fix fdt command in sandbox

Commit 90bac29a76bc8d649b41a55f2786c0abef9bb2c1 claims to fix this bug
that was introduced in commit a92fd6577ea17751ead9b50243e3c562125cf581
but doesn't actually make the change that the commit message describes.

Actually fix the bug this time.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_fdt.c b/common/cmd_fdt.c
index dc59fab..5878496 100644
--- a/common/cmd_fdt.c
+++ b/common/cmd_fdt.c
@@ -38,13 +38,13 @@
  */
 struct fdt_header *working_fdt;
 
-void set_working_fdt_addr(void *addr)
+void set_working_fdt_addr(ulong addr)
 {
 	void *buf;
 
-	buf = map_sysmem((ulong)addr, 0);
+	buf = map_sysmem(addr, 0);
 	working_fdt = buf;
-	setenv_addr("fdtaddr", addr);
+	setenv_ulong("fdtaddr", addr);
 }
 
 /*
@@ -123,7 +123,7 @@
 		if (control)
 			gd->fdt_blob = blob;
 		else
-			set_working_fdt_addr((void *)blob);
+			set_working_fdt_addr(addr);
 
 		if (argc >= 2) {
 			int  len;