dt-bindings: usb: dwc3: Limit num-hc-interrupters definition

Ensure that the number of XHCI secondary interrupters defined for a DWC3
based implementation is limited to 8.  XHCI in general can potentially
support up to 1024 interrupters.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20240102214549.22498-16-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>