regulator: fixed/gpio: Pull inversion/OD into gpiolib

This pushes the handling of inversion semantics and open drain
settings to the GPIO descriptor and gpiolib. All affected board
files are also augmented.

This is especially nice since we don't have to have any
confusing flags passed around to the left and right littering
the fixed and GPIO regulator drivers and the regulator core.
It is all just very straight-forward: the core asks the GPIO
line to be asserted or deasserted and gpiolib deals with the
rest depending on how the platform is configured: if the line
is active low, it deals with that, if the line is open drain,
it deals with that too.

Cc: Alexander Shiyan <shc_work@mail.ru> # i.MX boards user
Cc: Haojian Zhuang <haojian.zhuang@gmail.com> # MMP2 maintainer
Cc: Aaro Koskinen <aaro.koskinen@iki.fi> # OMAP1 maintainer
Cc: Tony Lindgren <tony@atomide.com> # OMAP1,2,3 maintainer
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> # EM-X270 maintainer
Cc: Robert Jarzmik <robert.jarzmik@free.fr> # EZX maintainer
Cc: Philipp Zabel <philipp.zabel@gmail.com> # Magician maintainer
Cc: Petr Cvek <petr.cvek@tul.cz> # Magician
Cc: Robert Jarzmik <robert.jarzmik@free.fr> # PXA
Cc: Paul Parsons <lost.distance@yahoo.com> # hx4700
Cc: Daniel Mack <zonque@gmail.com> # Raumfeld maintainer
Cc: Marc Zyngier <marc.zyngier@arm.com> # Zeus maintainer
Cc: Geert Uytterhoeven <geert+renesas@glider.be> # SuperH pinctrl/GPIO maintainer
Cc: Russell King <rmk+kernel@armlinux.org.uk> # SA1100
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Janusz Krzysztofik <jmkrzyszt@gmail.com> #OMAP1 Amstrad Delta
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>