dt-bindings: usb: dwc3: Add a property to reserve endpoints

Some of the endpoints may be reserved by hardware for different purposes,
e.g., tracing control and output. This is the case, for instance, on
Intel Merrifield and Moorefield platforms that reserve a few and USB driver
may not use them for the regular transfers. Add the respective bindings.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250212193116.2487289-2-andriy.shevchenko@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>