Incorrect VRx index selection for xWR6843AOP in visda.py line 82

[yfsun0327]

When processing radar data from the xWR6843AOP evaluation board, the visda.py script incorrectly stacks the radar cube channels at line 82. For the xWR6843AOP radar, x_cube1 should stack VRx 6, VRx 8, VRx 10, VRx 12 (corresponding to 0-based indices 5, 7, 9, 11) as in images/6843aop_ant.png:

Current behavior:

    x_cube1 = np.stack([radar_cube[:,6,:],
                        radar_cube[:,7,:],
                        radar_cube[:,9,:],
                        radar_cube[:,11,:]], axis=1)

Expected behavior:

    x_cube1 = np.stack([radar_cube[:,5,:],
                        radar_cube[:,7,:],
                        radar_cube[:,9,:],
                        radar_cube[:,11,:]], axis=1)