V4L/DVB (4366): Remove of couple of useless lines

A buffer was set just before an if block, and then again in both branches
of the if.  Obvious coding error.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>