V4L/DVB (6325): Double-free in cx23885_initdev

Both cx23885_initdev and cx23885_dev_setup free the device in their
error path so a failure in the latter causes a double-free. Since
cx23885_dev_setup is only called from cx23885_initdev, it should be safe
to remove its deallocation and leave the cleanup up to the allocating
function.

Coverity CID 1922.

Signed-off-by: Florin Malita <fmalita@gmail.com>
CC: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>