[media] ir-raw: Properly initialize the IR event (BZ#27202)

Changeset 4651918a changed the way events
are stored. However, it forgot to fix ir_raw_event_store_edge() to work
with the new way. Due to that, the decoders will likely do bad things.

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