dt-bindings: usb: msm-ssusb: Add properties for host mode PM suspend

Add optional properties to allow specifying whether host mode should
be started by default, and also whether to allow PM suspend
irrespective of runtime PM state.

Change-Id: Icba804874796a9da8a41880fd10121ef958cd242
Signed-off-by: Jack Pham <jackp@codeaurora.org>