remove Wpacked and cleanup unused warning flags

cmake/common/px4_base.cmake

src/drivers/px4flow/CMakeLists.txt

src/drivers/snapdragon_rc_pwm/CMakeLists.txt

src/drivers/uart_esc/CMakeLists.txt

src/firmware/posix/CMakeLists.txt

src/modules/commander/CMakeLists.txt

src/modules/mavlink/CMakeLists.txt

src/modules/mavlink/mavlink_tests/CMakeLists.txt

src/modules/navigator/CMakeLists.txt

src/modules/navigator/geofence.h

src/modules/navigator/mission.cpp

src/modules/sensors/CMakeLists.txt

src/modules/sensors/sensors.cpp

src/modules/simulator/CMakeLists.txt

src/modules/systemlib/CMakeLists.txt

src/modules/systemlib/param/param.c

src/modules/uavcan/CMakeLists.txt

src/platforms/posix/drivers/accelsim/CMakeLists.txt

src/platforms/posix/drivers/airspeedsim/CMakeLists.txt

src/platforms/posix/drivers/barosim/CMakeLists.txt