media: dvbdev: remove redundant initialization of variable ret

Variable ret is being ininitialized with a value that is never read.
The ininitializtion is redundant and can be removed. Move the variable
to the scope it is required.

Link: https://lore.kernel.org/linux-media/20220424154720.1356873-1-colin.i.king@gmail.com


Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>