V4L/DVB (5885): zr36067: Fix problems with module parameters

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>