treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

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 either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 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/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ASoC: max9877: Remove unused function declaration

Remove unused function declaration from header

Signed-off-by: Helen Koike <helen.koike@collabora.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>

ASoC: max9877: Remove unused function declaration

Remove unused function declaration from header

Signed-off-by: Helen Koike <helen.koike@collabora.co.uk>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

ASoC: MAX9877: add MAX9877 amp driver

The MAX9877 combines a high-efficiency Class D audio power amplifier
with a stereo Class AB capacitor-less DirectDrive headphone amplifier.

The max9877_add_controls() is called to register the MAX9877 specific
controls on machine specific init() of the machine driver.

The datasheet for the MAX9877 can find at the following url:
http://datasheets.maxim-ic.com/en/ds/MAX9877.pdf

[Slight edit to sort the ALL_CODECS entries -- broonie.]

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>