Revert Nav hold changes

[breadoven]

Removes one of the changes in #9947 which causes problems during fixed wing WP mode, Loiter at the last WP becomes unreliable. Also fixes the possibility of the same issue affecting WP Hold waypoints. Probably more likely to occur if the loiter radius is set too small.

[breadoven]

Hmmm, reverting the previous change didn't entirely fix this problem, according to HITL testing at least. Seems it occurs if you arrive at the final WP fast, e.g. following a steep dive from the previous WP, and have the loiter radius set too small. The plane can't turn tight enough at the final WP to stay within the distance required to keep the loiter turn active at which point it becomes unpredictable. Sometimes it turns back and recovers the loiter but a few times it flew off for a while before a forced turn was triggered (heading error > 170) and it flew back then loitered normally.

Can't remember seeing it do this before with the same loiter radius set, but it could just be that HITL had some wind active which was enough to make a difference. Need to do some more testing.