input: ft5x06_ts: add support for pinctrl framework

Migrate the Focaltech driver to use pinctrl framework for GPIO
configuration so that driver is compatible with targets that
use and targets that don't use pinctrl framework.

  This patch is propagated from 3.10 kernel
    commit: df621a0bebd6801f7fb9c76762cc9ac5f76e41e0
    input: ft5x06_ts: add support for pinctrl framework

Change-Id: I84fc2a6d30f831b4b054780b107ce105614855ea
Signed-off-by: Mao Li <maol@codeaurora.org>