media: dvb-usb-v2/gl861: remove an un-used header file

The header contained just internal definitions
and they are not used anymore.

Signed-off-by: Akihiro Tsukada <tskd08@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>