lmb: fix "implicit declaration of function 'lmb_free'" warning

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/lib_ppc/bootm.c b/lib_ppc/bootm.c
index 9db1c2e..3c1c18b 100644
--- a/lib_ppc/bootm.c
+++ b/lib_ppc/bootm.c
@@ -212,7 +212,7 @@
 		}
 
 		/* Delete the old LMB reservation */
-		lmb_free(lmb, of_flat_tree, fdt_totalsize(of_flat_tree));
+		lmb_free(lmb, (uint64_t)of_flat_tree, fdt_totalsize(of_flat_tree));
 
 		/* Calculate the actual size of the fdt */
 		actualsize = fdt_off_dt_strings(of_flat_tree) +