[media] staging: Fix comments and some typos in staging/media/*

linux-next:
I like to spend some time reading code, in doing so I have found some
typos in some of the comments.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>