memory leak was in send_outputs_pwm()

By default the baudrate in flight stack (Mavlink or NSH) 57600 and the default
baudrate of bootloader is 115200. So we may need to set different
baudrates.

The Mavlink reboot messages was only requesting the board to reboot.
If the flashed bootloader has a small or no timeout user will
never be able to update firmware.

The integrators were set to publish at 800Hz which was overwhelming
the CPU with the EKF running. This brings them in line with what we
get from the MPU6k device.

Unliked the MPU6000 from which this driver was based, the bosch
sensor does not have a requirement to handle registers at different
speeds.

Fixes #5601

Signed-off-by: Roman <bapstroman@gmail.com>

- avoid dividing by zero when calculating max delta output
- better comments when calculating max delta output
- better naming of functions and variables

Signed-off-by: Roman <bapstroman@gmail.com>

Signed-off-by: Roman <bapstroman@gmail.com>