GCC47: Fix warning in md5.c

md5.c: In function ‘MD5Final’:
md5.c:156:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
md5.c:157:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/lib/md5.c b/lib/md5.c
index 81a09e3..2ae4a06 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -153,8 +153,8 @@
 	byteReverse(ctx->in, 14);
 
 	/* Append length in bits and transform */
-	((__u32 *) ctx->in)[14] = ctx->bits[0];
-	((__u32 *) ctx->in)[15] = ctx->bits[1];
+	ctx->in32[14] = ctx->bits[0];
+	ctx->in32[15] = ctx->bits[1];
 
 	MD5Transform(ctx->buf, (__u32 *) ctx->in);
 	byteReverse((unsigned char *) ctx->buf, 4);