media: ti: cal: combine wdma irq handling

Instead of handling the WDMA START and END interrupts separately, we
need to handle both at the same time to better manage the inherent race
conditions related to CAL interrupts.

Change the code so that we have a single function,
cal_irq_handle_wdma(), which gets two booleans, start and end, as
parameters, which allows us to manage the race conditions in the
following patch.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>