Add permissions to all the module parameters so they can be queried and set
(when possible) via sysfs.

Add description for the vidmem parameter.

Change the video_nr parameter to an array, so that the video number can be
specified when a user has more than one card.  The driver would try to give
all cards the same number otherwise, which will fail for all cards after the
first.

The default_input option would only allow values of 0 or 1, contrary to the
description.  Allow values up to the number of inputs defined for the card.

Add description of lock_norm's different behavior for 1 and >1.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Acked-by: Ronald S. Bultje <rbultje@ronald.bitfreak.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>