USB: musb: forward debug mode feature to gadget

This is a patch for the musb usb controller.

It allows forwarding of the debug mode feature to its gadget in order
to be able to act as an ehci debug device.

This patch has been tested on an IGEPv2 board running a 2.6.35-rc1
kernel.

Signed-off-by: Stephane Duverger <stephane.duverger@gmail.com>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>