package/e2fsprogs: set xattrs for the root dir as well

The mke2fs binary copies the xattrs of the source directory when
creating an image, but this logic did not include the root directory of
the resulting image. A patch was sent upstream to fix this. Include the
patch in Buildroot to allow creating SELinux ready images at build time.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>