MFC r283067, r286118, r285638, r285935, r286778, r286780 and r286802:

MFC r283067, r286118, r285638, r285935, r286778, r286780 and r286802:
- Make the FIFO configuration a bit more flexible for the DWC OTG in
device side mode.
- Limit the number of times we loop inside the DWC OTG poll handler to
avoid starving other fast interrupts. Fix a comment while at it.
- Optimise the DWC OTG host mode driver's transmit path
- Optimise the DWC OTG host mode driver's receive path
- Minor code refactor to avoid duplicating code.
- Handle NYET high speed tokens and predict NAK'ing is up next.
- Fixes for HIGH speed ISOCHRONOUS traffic.

git-svn-id: svn://svn.freebsd.org/base/stable/10@287271 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f