If USB device reports class specific descriptors, it is currently the job of
device driver to parse the configuration to find the class specific data.
The new library functions parse the configuration descriptor and return class
specific interface and class specific endpoint descriptors.
Also, these new functions allow to retrieve the data from non-default alternate
settings without performing a switch to this setting. Switching to the
alternate setting currently implies the execution of UsbSetInterface function
that performs USB control trnasfer.
In some cases this switch is not desirable so the new functions
UsbGetInterfaceDescriptorSetting and UsbGetEndpointDescriptorSetting come
in handy.
Signed-off-by: Oleg Ilyasov <olegi@ami.com>
