media: vicodec: use new v4l2_m2m_ioctl_try_en/decoder_cmd funcs

Use the new helper functions for the try_de/decoder_cmd ioctls.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>