libfdt: Fix use of uninitialized variable in fdt_get_path()

My recent implemenetation of fdt_get_path() had a bug - the while loop
tested offset which was unitialized on the first iteration.  Depending
on code surrounding the call, this could cause fdt_get_path() to
return incorrect results.

This patch corrects the problem by applying some more correct thinking
to the loop condition.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

libfdt/fdt_ro.c

@@ -302,7 +302,7 @@ int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
 	buf[0] = '/';
 	p = 1;
 
-	while (offset < nodeoffset) {
+	while (nextoffset <= nodeoffset) {
 		offset = nextoffset;
 		tag = _fdt_next_tag(fdt, offset, &nextoffset);
 		switch (tag) {