usb: ehci-msm2: Add support for pinctrl framework

As the newer targets will be using pinctrl framework for gpio
configuration, our drivers need to be compatible with both set of targets
the one which do not use pinctrl and one which do. Adding support for both
these cases. ehci-msm2 driver can configure ext-hub-reset and resume
gpio's.

Change-Id: Id93920d55e468d3e435564e8fb9618c07401bf4c
Signed-off-by: Tarun Gupta <tarung@codeaurora.org>