ppc4xx: Remove compiler warning from previous commit

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/post/cpu/ppc4xx/cache.c b/post/cpu/ppc4xx/cache.c
index 92b751a..38e6e98 100644
--- a/post/cpu/ppc4xx/cache.c
+++ b/post/cpu/ppc4xx/cache.c
@@ -119,7 +119,7 @@
 	if (ints)
 		enable_interrupts ();
 
-	remove_tlb(virt, CACHE_POST_SIZE);
+	remove_tlb((u32)virt, CACHE_POST_SIZE);
 
 	return res;
 }