package.bbclass: Add a shortcut exit from the mkdir function

The mkdir function iterates over strings with many different operations,
even if ultimately the target already exists. This adds a check to the start
of the function so we don't waste time when the target already exists.

(From OE-Core rev: 06e188e673313f1eb9ae7d85ae64467c8d2a94b3)

(From OE-Core rev: 9509627e06ab4cf18c5bbf3f405ecf19a9f40287)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/package.bbclass

@@ -997,6 +997,8 @@ python populate_packages () {
                     seen.append(p)
 
             def mkdir_recurse(src, dest, paths):
+                if os.path.exists(dest + '/' + paths):
+                    return
                 while paths.startswith("./"):
                     paths = paths[2:]
                 p = "."