Move the orientation sanity-checks into the packet decode func.
Rationale: the packet handling func may otherwise read beyond the end of
device->last_axis_data.
Also expand them to cope with my test Huion's weird reporting.
Also correct the azimuth angle to align with GDK's presentation.
Most importantly, fix annoying comment typo.
https://bugzilla.gnome.org/show_bug.cgi?id=774265
61a57465ea