uart_esc: accept n channels instead of just 8.
uart_esc: accept n channels instead of just 8.

jlecoeur/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,darknight-007/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,mcgill-robotics/Firmware,dagar/Firmware,mcgill-robotics/Firmware,mje-nz/PX4-Firmware,jlecoeur/Firmware,krbeverx/Firmware,acfloria/Firmware,PX4/Firmware,dagar/Firmware,krbeverx/Firmware,PX4/Firmware,dagar/Firmware,mcgill-robotics/Firmware,dagar/Firmware,mcgill-robotics/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,darknight-007/Firmware,Aerotenna/Firmware,krbeverx/Firmware,jlecoeur/Firmware,Aerotenna/Firmware,acfloria/Firmware,mcgill-robotics/Firmware,darknight-007/Firmware,jlecoeur/Firmware,acfloria/Firmware,Aerotenna/Firmware,acfloria/Firmware,PX4/Firmware,krbeverx/Firmware,jlecoeur/Firmware,PX4/Firmware,darknight-007/Firmware,jlecoeur/Firmware,mcgill-robotics/Firmware,jlecoeur/Firmware,acfloria/Firmware,Aerotenna/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,darknight-007/Firmware,PX4/Firmware,Aerotenna/Firmware,krbeverx/Firmware,PX4/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,jlecoeur/Firmware,acfloria/Firmware,Aerotenna/Firmware,dagar/Firmware,mcgill-robotics/Firmware