this commit is a combination of the following changes, which
significantly refactors usb core and class drivers.
1. unify usb buffers of each class driver to reduce iram usage
currently, many class drivers allocate their own buffer to receive
control out data, which is a waste of iram.
share one common buffer for that usage to address the issue.
2. simplify control request handling by implicitly receiving write
request data packets
change 1 above fixed the data destination. therefore, having the core
receive the data allows us to reduce the class driver's work and
simplifies the api.
3. enhance usb core's control request handling and unify the legacy
driver api
in order to implement change 2, both the legacy and new driver apis
should be supported. so that, using the designware driver as a
reference, the new driver api functionality is move into usb core.
this simplifies the usb device drivers by requiring them to implement
only the functionalities equivalent to the legacy api.
tested with ipodvideo(arc) and erosqnative(designware)
Change-Id: I3627daa90278751f599e2108ec150ec3f8f6c524
