media: allegro: warn if response message has an unexpected size

The driver uses structs to parse the responses from the VCU and expects
a certain size of the responses. However, the size and format of the
mails is not stable across firmware versions. Therefore, print a warning
if the size does not match the expected size to warn the user that
strange things might happen.

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>