media: docs: move driver-specific info to driver-api

Those documents don't really describe the driver API.

Instead, they contain development-specific information.

Yet, as the main index file describes the content of it as:

"how specific kernel subsystems work
from the point of view of a kernel developer"

It seems to be the better fit.

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.435762997@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: dvb: point to the location of the old README.dvb-usb file

This file got renamed, but the references still point to the
old place.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>

gp8psk: Fix DVB frontend attach

The DVB binding schema at the DVB core assumes that the frontend is a
separate driver. Faling to do that causes OOPS when the module is
removed, as it tries to do a symbol_put_addr on an internal symbol,
causing craches like:

WARNING: CPU: 1 PID: 28102 at kernel/module.c:1108 module_put+0x57/0x70
Modules linked in: dvb_usb_gp8psk(-) dvb_usb dvb_core nvidia_drm(PO) nvidia_modeset(PO) snd_hda_codec_hdmi snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm snd_timer snd soundcore nvidia(PO) [last unloaded: rc_core]
CPU: 1 PID: 28102 Comm: rmmod Tainted: P WC O 4.8.4-build.1 #1
Hardware name: MSI MS-7309/MS-7309, BIOS V1.12 02/23/2009
Call Trace:
dump_stack+0x44/0x64
__warn+0xfa/0x120
module_put+0x57/0x70
module_put+0x57/0x70
warn_slowpath_null+0x23/0x30
module_put+0x57/0x70
gp8psk_fe_set_frontend+0x460/0x460 [dvb_usb_gp8psk]
symbol_put_addr+0x27/0x50
dvb_usb_adapter_frontend_exit+0x3a/0x70 [dvb_usb]

From Derek's tests:
"Attach bug is fixed, tuning works, module unloads without
crashing. Everything seems ok!"

Reported-by: Derek <user.vdr@gmail.com>
Tested-by: Derek <user.vdr@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[media] dvb-usb: move it to drivers/media/usb/dvb-usb

As media/dvb will be removed, move it to a proper place.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>