[media] mceusb: fix keybouce issue after parser simplification

Something I failed to notice while testing the mceusb RLE buffer
decoding simplification patches was that we were getting an extra event
from the previously pressed key.

As was pointed out to me on irc by Maxim, this is actually due to using
ir_raw_event_store_with_filter without having set up a timeout value.
The hardware has a timeout value we're now reading and storing, which
properly enables the transition to idle in the raw event storage
process, and makes IR decode behave correctly w/o keybounce.

Also remove no-longer-used ir_raw_event struct from mceusb_dev struct
and add as-yet-unused enable flags for carrier reports and learning
mode, which I'll hopefully start wiring up sooner than later. While
looking into that, found evidence that 0x9f 0x15 responses are only
non-zero when the short-range learning sensor is used, so correct the
debug spew message, and then suppress it when using the standard
long-range sensor.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>