media: allegro: fix module removal if initialization failed

If the module probe finished, but the firmware initialization failed,
removing the module must not revert the firmware initialization.

Add a field to track the status of the firmware initialization and only
roll it back, if the firmware was successfully initialized.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>