simulator_mavlink: switch battery max and min to fix simultion
simulator_mavlink: switch battery max and min to fix simultion

In 3e6e1f5c2b042accca72346273fc1755dd7670fa the simulated battery
percentage was reversed. I'm assuming because of the possibly
missleading variable name. Now I'm fixing it by switching the
maximum and minimum voltage such that the name is not misleading anymore
but it still works as expected.

krbeverx/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,dagar/Firmware,acfloria/Firmware,dagar/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,dagar/Firmware,krbeverx/Firmware,PX4/Firmware,dagar/Firmware,PX4/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,dagar/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,PX4/Firmware,krbeverx/Firmware