[media] cx231xx: use TRANSFER_TYPE enum for cleanup

Most calls to cx231xx_capture_start() already use the values from
TRANSFER_TYPE, but cx231xx_capture_start() and
cx231xx_initialize_stream_xfer() were hand coding the values.
Use the named values (81 is never passed in), and simplify
cx231xx_capture_start(), as the switch statements were identical and
pcb_config->config_num is a u8, so any non-zero config got the same
result.

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