update docs to remove misleading information about MTU
update docs to remove misleading information about MTU

bluesquall/lcm,adeschamps/lcm,lcm-proj/lcm,lcm-proj/lcm,adeschamps/lcm,bluesquall/lcm,bluesquall/lcm,lcm-proj/lcm,lcm-proj/lcm,adeschamps/lcm,bluesquall/lcm,adeschamps/lcm,lcm-proj/lcm,lcm-proj/lcm,lcm-proj/lcm,bluesquall/lcm,adeschamps/lcm,adeschamps/lcm,lcm-proj/lcm,adeschamps/lcm,adeschamps/lcm,bluesquall/lcm,bluesquall/lcm