package/python-kmod: fix licensing

Commit 2add559e506e (package/python-kmod: new package) listed LGPL-2.1+
(aka -or-later) as the licensed applicable. However, thode contains the
following blurbs:

    # python-kmod is free software: you can redistribute it and/or modify it under
    # the terms of the GNU Lesser General Public License version 2.1 as published
    # by the Free Software Foundation.

There is no mention of the usual "or, at your option, any later
version".

As such, the license is reall LGPL-2.1-only.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/python-kmod/python-kmod.mk

@@ -9,7 +9,7 @@
 PYTHON_KMOD_VERSION = 0.9.2
 PYTHON_KMOD_SITE = $(call github,maurizio-lombardi,python-kmod,v$(PYTHON_KMOD_VERSION))
 PYTHON_KMOD_SETUP_TYPE = setuptools
-PYTHON_KMOD_LICENSE = LGPL-2.1+
+PYTHON_KMOD_LICENSE = LGPL-2.1
 PYTHON_KMOD_LICENSE_FILES = COPYING.LESSER
 PYTHON_KMOD_DEPENDENCIES = host-python-cython kmod