Tilt scale correction for certain resolutions

"mTiltXScale" does not reflect the resolutions of the tilts of the devices,
so that the AXIS_TILT can be corrupted when a device reports its tilt with
a certain resolution rather than a degree based output.

Test: manual

Signed-off-by: Tatsunosuke Tobita <tatsunosuke.tobita@WacomMfG.corp-partner.google.com>
Change-Id: I35d866a8cd2778a34904229cf8c475b3118b9c2b