win32: Fix tilt from Wintab devices

win32: Fix tilt from Wintab devices

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