V4L/DVB: lgs8gxx: remove firmware for lgs8g75

The recently added support for lgs8g75 included some 8051 machine code
without accompanying source code.  Replace this with use of the
firmware loader.

Compile-tested only.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>