Input: focaltech - report finger width to userspace

Focaltech touchpads report finger width in packet[5] of absolute packet.
Range for width in raw format is 0x10 - 0x70. Second half-byte is always 0.
0xff is reported, when a large contact area is detected.
This can be handled in userspace.

Signed-off-by: Dmitry Tunin <hanipouspilot@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>