V4L/DVB (5462): Add Logitech ViewPort AV 100

Logitech ViewPort AV 100 has the same internals as Cisco VT Camera. 
Fixing Pwc driver to handle it properly. 
Also, fixed the comments for both cameras.
Thanks to Martin Rubli for pointing me this.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>