MPC_THR_HOVER gets passed unconstrained to the thrust setpoint in manual mode.

[dlwalter]

Describe the bug
An incorrect value of MPC_THR_HOVER will get passed unconstrained to the manual thrust setpoint. In 1.8.2 the manual thrust setpoint was constrained between MPC_THR_MIN and MPC_THR_MAX. If the user entered a MPC_THR_HOVER of 50 instead of 0.50 a centered stick would result in a thrust setpoint of 50 where the mixer expects values between 0 and 1.0.

To Reproduce
Steps to reproduce the behavior:
Set MPC_THR_HOVER to a value of 59 (instead of the correct 0.59). In QGC this is would have to be entered as 5900 but in a startup script as 59.

Expected behavior
The hover thrust setpoint should not be greater than 1.0, or MPC_THR_MAX

Log Files and Screenshots
https://review.px4.io/plot_app?log=4a38b5fc-4684-4b16-9313-16dcda6294cd

Yeah, this was a dumb mistake on my part to fat finger the entry, but in 1.8.2 I would have to fat finger two separate parameters. It's up to you guys if you want to protect against this kind of dumb.