pinctrl: samsung: Move retention control from mach-s5pv210 to the pinctrl driver

This patch moves pad retention control from S5PV210 machine code to
Exynos pin controller driver. This helps to avoid possible ordering
and logical dependencies between machine and pin control code. Till
now it worked fine only because sys_ops for machine code and pin
controller were called in registration order.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
For mach-s5pv210:
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>