DWC3 host support

[Angus Ainslie]

On 2022-07-16 06:02, Angus Ainslie wrote:
> Hi Michal,
> 
> I recently rebased my librem5 tree onto the latest u-boot-imx branch
> and the dwc3 host mode stopped working.
> 

Further debugging indicates that the "U-Boot XHCI Host Controller" is 
detected but downstream USB 2 hubs and storage devices are not.

> I bisected it down to this commit:
> 
> 142d50fbce7c364a74f5e8204dba491b9f066e6c usb: dwc3: Add support for
> usb3-phy PHY configuration
> 
> Reverting that commit allows usb host mode to work on the librem5 
> again.
> 
> Should this initialization go into an SOC specific glue_configure 
> function ?
> 
> Is the imx8mq.dtsi missing something that will keep usb host working
> with this patch ?
> 
> Does this break usb host on other imx8mq devices ?
> 
> Thanks
> Angus