media: gspca: remove redundant assignment of variable n

The variable n is being assigned a value that is never read, it is
being reassigned a different value a few statements later. The
assignment is redundant and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>