[media] staging: easycap: Initialize 'ntsc' parameter before usage

This parameter is now initialized at init_easycap(),
this way we assure it won't be used uninitialized.

Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>