MC mixer: prioritize roll/pitch over yaw for full airmode

[bkueng]

Only the full airmode gives equal priority to roll, pitch and yaw, the others reduce yaw priority. I find that behavior also desirable in full airmode, as it improves roll/pitch tracking for large yaw sp changes (for example). I have already flown with this over the last weeks/months.

Here are some logs:

• https://logs.px4.io/plot_app?log=1548c302-3172-4cad-985c-b233903b2f97
• https://logs.px4.io/plot_app?log=fb569865-77b1-4a8c-92b5-9888ed9460c2
• https://logs.px4.io/plot_app?log=1a3fb8a8-770e-411c-98ed-87b5f4d79a0a
• https://logs.px4.io/plot_app?log=d76881ac-9b21-4cd9-9489-2e76c2ac9fbb

[bresch]

Nice! I'll try that on my racer