rbutil: Merge rbutil with utils folder.

rbutil uses several components from the utils folder, and can be
considered part of utils too. Having it in a separate folder is an
arbitrary split that doesn't help anymore these days, so merge them.

This also allows other utils to easily use libtools.make without the
need to navigate to a different folder.

Change-Id: I3fc2f4de19e3e776553efb5dea5f779dfec0dc21

utils/mkimxboot/md5.h

@@ -0,0 +1,25 @@
+#ifndef _MD5_H
+#define _MD5_H
+
+#ifndef uint8
+#define uint8  unsigned char
+#endif
+
+#ifndef uint32
+#define uint32 unsigned long int
+#endif
+
+typedef struct
+{
+    uint32 total[2];
+    uint32 state[4];
+    uint8 buffer[64];
+}
+md5_context;
+
+void md5_starts( md5_context *ctx );
+void md5_update( md5_context *ctx, uint8 *input, uint32 length );
+void md5_finish( md5_context *ctx, uint8 digest[16] );
+
+#endif /* md5.h */
+