phy-msm-usb: Enable external id irq wakeup capability

This change enables external id irq wakeup capability for
USB host mode functionality to work in system suspend case.

CRs-Fixed: 649428
Change-Id: Ieedf9a7314d21cf9a144a521bfe43300cc8f5fcb
Signed-off-by: Saket Saurabh <ssaurabh@codeaurora.org>