media: allegro: process all pending status mbox messages

media: allegro: process all pending status mbox messages

Under certain circumstances, not every message written by the MCU to the
status mailbox may trigger a corresponding interrupt. This is likely when
multiple messages are generated in a very short period of time. Since the
current implementation only processes one message per interrupt, even if
multiple messages are already available in the mailbox, expected messages
are either not received or are processed late. This leads to various
subsequent problems and causes the driver to no longer function properly.

The behavior has been adjusted so that after an interrupt, all messages
available in the mailbox are processed.

Signed-off-by: Matthias Fend <matthias.fend@emfend.at>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>