usb: gadget: udc: atmel: don't disable enpdoints we don't own

UDC driver should NEVER do anything behind
udc-core's back, so let's stop disabling endpoints
we don't exactly own - rather we provide as
resources for gadget drivers. This fixes the
regression reported by Gil.

Reported-by: Gil Weber <gil.weber@servelec-technologies.com>
Tested-by: Gil Weber <gil.weber@servelec-technologies.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>