soc: samsung: Rename Samsung and Exynos to lowercase

Fix up inconsistent usage of upper and lowercase letters in "Samsung"
and "Exynos" names.

"SAMSUNG" and "EXYNOS" are not abbreviations but regular trademarked
names. Therefore they should be written with lowercase letters starting
with capital letter.

The lowercase "Exynos" name is promoted by its manufacturer Samsung
Electronics Co., Ltd., in advertisement materials and on website.

Although advertisement materials usually use uppercase "SAMSUNG", the
lowercase version is used in all legal aspects (e.g. on Wikipedia and in
privacy/legal statements on
https://www.samsung.com/semiconductor/privacy-global/).

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: Add SPDX license identifiers

Replace GPL license statements with SPDX GPL-2.0 license identifiers.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: pmu: Remove duplicated define for ARM_L2_OPTION register

The register ARM_L2_OPTION (0x2608 in Exynos4 and Exynos5 PMU) was
defined twice. Both names were used in the Exynos542x code. Simplify
this.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

soc: samsung: pmu: Constify arrays with PMU data

Arrays storing values for Power Management Unit for given sleep mode can
be made const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

drivers: soc: Add support for Exynos PMU driver

This patch moves Exynos PMU driver implementation from "arm/mach-exynos"
to "drivers/soc/samsung". This driver is mainly used for setting misc
bits of register from PMU IP of Exynos SoC which will be required to
configure before Suspend/Resume. Currently all these settings are done
in "arch/arm/mach-exynos/pmu.c" but moving ahead for ARM64 based SoC
support, there is a need of this PMU driver in driver/* folder.

This driver uses existing DT binding information and there should
be no functionality change in the supported platforms.

Signed-off-by: Amit Daniel Kachhap <amitdanielk@gmail.com>
[tested on Peach-Pi (Exynos5880)]
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[for testing on Trats2 (Exynos4412) and Odroid XU3 (Exynos5422)]
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[k.kozlowski: Rebased, add necessary infrastructure for building and
selecting drivers/soc because original patchset was on top of movement
SROMc to drivers/soc]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>