arm/dt: msm8974: Use hs_phy_irq to receive wake-up events in LPM

Enable support for hs_phy_irq which is used by DWC3 to notify
wakeup events e.g. BSVHV interrupts on cable connect via separate
interrupt line. This is required to use USB cable connect event as
wakeup capable.

Change-Id: I80fbaa4f47b2949244413d821a9bde110179fd75
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>