uboot-imx

tegra20: usb: rework set_host_mode

This allows for two things:
- VBus GPIO may be used on other ports than the OTG one
- VBus GPIO may be low active if specified by DT

Signed-off-by: Lucas Stach <dev@lynxeye.de>
CC: Stephen Warren <swarren@wwwdotorg.org>
CC: Tom Warren <TWarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>