synaptics_3k: Do not hardcode pressure & width

The synaptics_3k driver has the pressure and width values hardcoded
into the params. This makes adjusting for width and pressure slightly
more confusing/work than it should be. Get rid of the hardcoded values
and use defines.

[NOTE: Using MAX_WIDTH for ABS_MT_PRESSURE may not be correct, but we'll
keep it that way for now, since that's the way the driver seems to be configured.]

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
synaptics_3k: Improve touchscreen sensitivity

Increasing sensitivity in this manner has worked well on for the d2 touchscreen
driver. Apply to m7.

0xlab did similar for DevKit8000 here:
https://gitorious.org/0xlab-kernel/kernel/commit/f5a258642408fd7820d7aefc58d1eb3719e06b8a

Signed-off-by: Luis Cruz <ljc2491@gmail.com>