V4L/DVB (11284): Fix i2c code of flexcop-driver for rare revisions

This patch adds a workaround in the i2c-code of the flexcop-driver to
fix support for SkyStar2 rev 2.7. There are not many devices out
there, that's why this bug was not revealed earlier.

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>