media: adv7604: Prevent out of bounds access

These can only be accessed with CAP_SYS_ADMIN so it's not a critical
security issue.  The problem is that "page" is controlled by the user in
the ioctl().  The test to see if the bit is set in state->info->page_mask
is not sufficient because "page" can be very high and shift wrap around
to a bit which is set.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>