usb: phy: phy-am335x: bypass first VBUS sensing for host-only mode

usb: phy: phy-am335x: bypass first VBUS sensing for host-only mode

To prevent VBUS contention, the am335x MUSB phy senses VBUS first before
transitioning to host mode. However, for host-only mode, VBUS could be
directly tied to 5V power rail which could prevent MUSB transitions to
host mode.

This change receives dr_mode of the controller then bypass the first
VBUS sensing for host-only mode, so that MUSB can work in host mode
event if VBUS is tied to 5V.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>