Update submodule ecl to latest Tue Aug 11 00:39:49 UTC 2020

    - ecl in PX4/Firmware (9e3f563): PX4/PX4-ECL@7eb2b08
    - ecl current upstream: PX4/PX4-ECL@ec93490
    - Changes: PX4/PX4-ECL@7eb2b08...ec93490

    ec93490 2020-08-10 kamilritz - geo test change to arc length
98dec6a 2020-08-10 kamilritz - add tests for waypoint_from_line_and_distance()
60388a8 2020-08-10 kamilritz - Geo: Fix double correcting for negative distance
6feb28c 2020-08-10 Paul Riseborough - EKF: Convert EKF-GSF yaw estimator from matlab to sympy derived equations (#871)
9d7d502 2020-08-09 kamilritz - std::sin -> sin
4ab364f 2020-08-09 kamilritz - Make conversion from float to double explicite
9ea3468 2020-07-07 Julian Kent - Negative distances go in the opposite direction
b7e49f2 2020-08-09 kamilritz - Update change indication
4970088 2020-08-09 kamilritz - Update matrix version
d7568d5 2020-07-28 kamilritz - extend firmware build checks
310b989 2020-08-06 kamilritz - refactor start of gps into separate function