media: staging: use strscpy() instead of strlcpy()

There are a few left overs at staging which were still using the
deprecated strlcpy() function.

Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>