dc3dd: gettextize to match newer gettext version

Because dc3dd is being autoreconfigured and comes with an old gettext
infra, gettextize needs to be called so that the infra is updated to
match the newer version used in Buildroot.

Commit b36d57fa included a patch to add the definition of MKDIR_P to
po/Makefile.in.in in order to fix autobuild failures that ocurred when
host-gettext was built before dc3dd. This patch is no longer necessary
as gettextize adds a new Makefile template which contains the needed
definition, so drop it.

Signed-off-by: Rodrigo Rebello <rprebello@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>