net: qrtr: Handle IPCR control port format of older targets

The destination port value in the IPCR control buffer on older
targets is 0xFFFF. Handle the same by updating the dst_port to
QRTR_PORT_CTRL.

Signed-off-by: Vignesh Viswanathan <quic_viswanat@quicinc.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>