media: dvb: symbol fixup for dvb_attach()

In commit 9011e49d54dc ("modules: only allow symbol_get of
EXPORT_SYMBOL_GPL modules") the use of symbol_get is properly restricted
to GPL-only marked symbols. This interacts oddly with the DVB logic
which only uses dvb_attach() to load the dvb driver which then uses
symbol_get().

Fix this up by properly marking all of the dvb_attach attach symbols as
EXPORT_SYMBOL_GPL().

Fixes: 9011e49d54dc ("modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules")
Cc: stable <stable@kernel.org>
Reported-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-media@vger.kernel.org
Cc: linux-modules@vger.kernel.org
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://lore.kernel.org/r/20230908092035.3815268-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: ddbridge: use the ddbridge's own dummy fe driver

Cleanup the ddbridge's dummy driver by removing the parts
that aren't needed by ddbridge, adding it to the building
system and changing the binding at the driver to use the
newer function name.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: ddbridge-dummy_fe: do some vars and function renames

As the name of this driver is now ddbridge-dummy, do some
renames internally.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: ddbridge: copy the dvb_dummy_fe driver to ddbridge

As we'll be transforming the dvb-dummy-fe driver soon into a
virtual driver, let's first copy the existing one to ddbridge
as-is, as it is needed there.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>