gpio_keypad: Fix key reporting [1/1]

gpio_keypad: Fix key reporting [1/1]

PD#172258: pio_keypad: Fix key reporting [1/1]

the following issues have been fixed :
1. didn't report any keys to userspace.
2. the push down of key is reported as push up.
3. no event is reported when press key for the first time.

adjust the key event value by changing the gpio flag for
atom board, as follows:
1. the event value "0" is replaced  to "1" when push down.
2. the event value "1" is replaced  to "0" when push up.

Change-Id: Ia207506df25ea604bce4b6ae9573a981fe664061
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: Tellen Yu <tellen.yu@amlogic.com>
Signed-off-by: Yingyuan Zhu <yingyuan.zhu@amlogic.com>