media: usb: dvb-usb: remove old friio driver

friio drivers is unused and un-compilable since
commit b30cc07d ("media: dvb-usb/friio, dvb-usb-v2/gl861: decompose
friio and merge with gl861"). Let's remove it.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Cc: Akihiro Tsukada <tskd2@yahoo.co.jp>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>