[PATCH] USB gadget: dualspeed {run,compile}-time flags
This is the first several autoconfig patches; please merge.
This particular one abstracts dual-speed (high and full)
support.
Support some more autoconfiguration for gadget drivers.
Run-time:
* Add gadget->is_dualspeed flag for controllers to set.
* Tested by "ethernet" gadget, to decide whether certain
operations are errors or not.
* Turned on by net2280.
Compile-time
* Generic CONFIG_USB_GADGET_DUALSPEED, not net2280-specific.
* Used by "ethernet" gadget, to decide whether to
include extra code and data for dual-speed support.
* Turned on by net2280.
The basic idea behind this, and other autoconfig patches yet to come,
is minimizing the controller-specific compile-time configuration
needed by gadget drivers.