V4L/DVB: ivtv: Add firmare monitoring and debug mode to ignore firmware problems

>From Ian's e-mail:
When a device is opened the firmware state will be checked. If it isn't
responding then the open will fail with -EIO.  Due to the nature of the
hardware, a single failed check will block everything since we don't know
exactly what has failed. A side effect of this is the blocking of debug
access, so an additional debug level has been created which allows the block
to be bypassed.

Andy Walls' modifications:
I modified Ian's patch to add a separate fw_debug module parameter to change
the driver's behavior, as opposed to using the normal debug module parameter.
The fw_debug module parameter is only available when CONFIG_VIDEO_ADV_DEBUG
is set.
I also made some minor whitespace adjustments and changed some warning
messages to be a bit more specific.  s/happy/glad/g

Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>