media: vidtv: Move s302m specific fields into encoder context

A few fields used only by the tone generator in the s302m encoder
are stored in struct vidtv_encoder. Move them into
struct vidtv_s302m_ctx instead. While we are at it: fix a
checkpatch warning for long lines.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>