usb: chipidea: host: add vbus regulator control

usb: chipidea: host: add vbus regulator control

For boards which have board level vbus control (eg, through gpio), we
need to vbus operation according to below rules:
- For host, we need open vbus before start hcd, and close it
after remove hcd.
- For otg, the vbus needs to be on/off when usb role switches.
When the host roles begins, it opens vbus; when the host role
finishes, it closes vbus.

We put vbus operation to host as host is the only vbus user,
When we are at host mode, the vbus is on, when we are not at
host mode, vbus should be off.

Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>