arm/dts: hammerhead: Configure UART RX gpio line as wakeup irq line

attempt to fix leftover bt disconnect issue by using irq changes from caf

reference caf commit: I775c17d4d36b08225b32063131473567c2d16f9c

Change-Id: I92cb1c3a3688e1914998658e39ee8d9886ca8231