package/python-pillow: remove host-python-pillow support

host-python-pillow was needed to build optee-os from STMicroelecronics
during its rc versions but is is not needed anymore in the release.
It is then useless to keep this support.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>