ARM: plat-iop: instantiate GPIO from platform device

ARM: plat-iop: instantiate GPIO from platform device

This converts the IOP32x and IOP33x platforms to pass their
base address offset by a resource attached to a platform device
instead of using static offset macros implicitly passed
through <linux/gpio.h> including <mach/gpio.h>. Delete the
local <mach/gpio.h> and <asm/hardware/iop3xx-gpio.h> headers
and remove the selection of NEED_MACH_GPIO_H.

Pass the virtual address as a resource in the platform device
at this point for bisectability, next patch will pass the
physical address as is custom.

Cc: Lennert Buytenhek <kernel@wantstofly.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>