The current hid-multitouch driver only allow the report of two
orientations, vertical and horizontal. We use the Azimuth orientation
usage 0x3F under the Digitizer usage page to report orientation if the
device supports it.

Changelog:
  v1 -> v2:
   - Fix commit message.
   - Remove resolution reporting for ABS_MT_ORIENTATION.
  v2 -> v3:
   - Fix commit message.
  v3 -> v4:
   - Fix ABS_MT_ORIENTATION ABS param range.
   - Don't set ABS_MT_ORIENTATION in ABS_DG_HEIGHT when it is already
     set by ABS_DG_AZIMUTH.
  v4 -> v5:
   - Improve multi-touch-protocol.rst documentation.
Signed-off-by: Wei-Ning Huang <wnhuang@chromium.org>
Signed-off-by: Wei-Ning Huang <wnhuang@google.com>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-by: Henrik Rydberg <rydberg@bitmath.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>