delete examples mc_pos_control_multiplatform

src/examples/mc_pos_control_multiplatform/CMakeLists.txt

src/examples/mc_pos_control_multiplatform/mc_pos_control.cpp

src/examples/mc_pos_control_multiplatform/mc_pos_control.h

...ples/mc_pos_control_multiplatform/mc_pos_control_main.cpp

...ples/mc_pos_control_multiplatform/mc_pos_control_params.c

...ples/mc_pos_control_multiplatform/mc_pos_control_params.h

..._pos_control_multiplatform/mc_pos_control_start_nuttx.cpp