usb: xhci-msm-hsic: Add wakeup gpio support for out of band remote wakeup

Some peripherals connected to HSIC host controller cannot use in-band
remote-wakeup to wakeup host controller from usb bus suspend and use
gpio instead. Add support for wakeup gpio to support out of band
remote-wakeup.

Change-Id: I9c7299bab5dd5c2a9c7d664afe6dbf0b7f7e6e19
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>