media: dvb-frontends/stv0910: add SPDX license identifier

As it is clear that the driver is licensed under the terms of GPLv2-only
by now, add a matching SPDX license identifier to all driver files.

Cc: Ralph Metzler <rjkm@metzlerbros.de>
Cc: Manfred Voelkel <mvoelkel@DigitalDevices.de>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: frontends/stv0910: add field offsets to field defines

Each field (FSTV0910_XX) is declared as reg/off/unused/sign/mask. Add
the missing offset value to the defines.

Picked up from dddvb master, commit 8a1f27c3d22c ("add field offset to
field defines") by Ralph Metzler <rjkm@metzlerbros.de>, adapted to
match the comment style in the mainline driver.

Cc: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: dvb-frontends/stv0910: cosmetics: fixup comments, misc

Fix up block comment style, whitespaces, c++ style comments et al.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: dvb-frontends: add ST STV0910 DVB-S/S2 demodulator frontend driver

This adds a multi frontend driver for the ST STV0910 DVB-S/S2 demodulator
frontends. The driver code originates from the Digital Devices' dddvb
vendor driver package as of version 0.9.29, and has been cleaned up from
core API usage which isn't supported yet in the kernel, and additionally
all obvious style issues have been resolved. All camel case and allcaps
have been converted to kernel_case and lowercase. Patches have been sent
to the vendor package maintainers to fix this aswell. Signal statistics
acquisition has been refactored to comply with standards.

Permission to reuse and mainline the driver code was formally granted by
Ralph Metzler <rjkm@metzlerbros.de>.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Tested-by: Richard Scobie <r.scobie@clear.net.nz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>