media: dvb_frontend: initialize variable s with FE_NONE instead of 0

GIT_AUTHOR_NAME=Colin King
GIT_AUTHOR_EMAIL=colin.king@canonical.com

In a previous commit, we added FE_NONE as an unknown fe_status.
Initialize variable s to FE_NONE instead of the more opaque value 0.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>