Input: bcm5974 - Drop the logical dimensions

The logical scale is used to produce special finger width values to
userspace, but has become an unnecessary restriction for everything
else.  Also, the bcm5974 trackpads are very accurate and work well
without hysteresis.

This patch simplifies the driver and device data by removing the
logical scale, and by moving the special synaptics code out of the
main path.  Also add the orientation range, needed in a subsequent
patch, to the device configuration.
Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>