mtecs blocks: fix warning
fw pos ctrl l1 main: fix warning
fw pos ctrl l1 main: initialize all subscriptions
fw pos ctrl l1 main: remove unused modes
fw pos ctrl l1 main: remove several unused vars
fw pos ctrl l1 main: init target_bearing
fw pos ctrl l1 main: remove never used var
fw pos ctrl l1 main: remove code  with no effect
merged master
Merge pull request #1102 from PX4/fwposwarnings

FW pos control: fix warnings and remove code