When a device uses GPIO interrupt, its driver assumes that GPIO
should be INPUT mode. However, GPIO of SAMSUNG SoC is sepated to
INPUT mode and INTERRUPT mode. They are set by 0x0 and 0xF in GPIO
control register. If the register is set to INPUT mode, the
interrupt never occur. Therefore, it's necessary to set INTERRUPT
mode instead of INPUT mode when the pin is used for GPIO interrupt.

This patch inserts the bitmap_gpio_int member in struct samsung_
gpio_chip in order to represent use of GPIO interrupt for each pin
and sets the related bit when s5p_register_gpio_interrupt function
is called.
Signed-off-by: Eunki Kim <eunki_kim@samsung.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>