[media] cx231xx: don't DMA to random addresses

Commit 7a6f6c29 (cx231xx: use
URB_NO_TRANSFER_DMA_MAP) was intended to avoid mapping the DMA buffer
for URB twice. This works for the URBs allocated with usb_alloc_urb(),
as those are allocated from cohernent DMA pools, but the flag was also
added for the VBI and audio URBs, which have a manually allocated area.
This leaves the random trash in the structure after allocation as the
DMA address, corrupting memory and preventing VBI and audio from
working. Letting the USB core map the buffers solves the problem.

Cc: stable@kernel.org
Signed-off-by: David Dillow <dave@thedillows.org>
Cc: Sri Deevi <srinivasa.deevi@conexant.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>