V4L/DVB: cx23885, cx25840: Change IR measurment records to use struct ir_raw_event

The CX23885 and CX25840 modules were using their own simple
IR pulse width measurement record type which required conversion
when passing to the new IR core.  This change makes that record type
consistent with the new IR core and removes a data conversion.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>