pinctrl: mvebu: add driver for Armada AP806 pinctrl

This commit adds a pinctrl driver for the pin-muxing controller found in
the AP806 part of the Marvell Armada 7K and 8K SoCs. Its register
interface is compatible with the one used by previous mvebu pin
controllers, so the common logic in drivers/pinctrl/mvebu/pinctrl-mvebu.c
is used.

Signed-off-by: Hanna Hawa <hannah@marvell.com>
Reviewed-by: Shadi Ammouri <shadi@marvell.com>
[updated for mvebu pinctrl changes
 - converted to simple_mmio
 - removed unimplemented .remove function
 - removed DTS description
  - converted  to use syscon/regmap
 --rmk]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>