media: mtk-cir: remove superfluous ir_raw_event_reset()

This IR receiver has two limitations:

1) Any IR pulse or space longer than 12ms will be truncated to 12ms

2) Any pulses/spaces after the first 68 are lost

ir_raw_event_reset() won't help here. If the IR cannot be decoded, any
decoder should reset itself, and if it does not, this is a bug in the
decoder.

Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>