ush: ehci: initialize altnext pointers in QH

A QH's overlay QTD altnext pointer should be explicitly marked invalid
so that the EHCI controller knows to look at the QTD next pointer. Update
the driver to do this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
usb: ehci: fully align interrupt QHs/QTDs

These data structures are passed to cache-flushing routines, and hence
must be conform to both the USB the cache-flusing alignment requirements.
That means aligning to USB_DMA_MINALIGN. This is important on systems
where cache lines are >32 bytes.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
LOCAL: ARM: tegra: enable USB keyboard on Venice2

Useful at least for tegrasim testing.

Signed-off-by: Stephen Warren <swarren@nvidia.com>