media: rtl28xxu: add support for Sony CXD2837ER slave demod

Since 2018 some new revisions of RTL2832P based devices having
Sony CXD2837ER as a slave demodulator instead of Panasonic MN88473.
CXD2837ER handled in DVB_CXD2841ER module but it's has a lack of control.
So slave demod has to be reseted by GPIO0 before detecting to woke up
CXD2837ER.

Signed-off-by: Nikita Gerasimov <nikitych@yandex.ru>
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>