input: touchscreen: Add the optimized mcs6000 touchscreen driver.
This is the optimized mcs6000 touchscreen driver. Based on mcs6000 touch screen driver from 2.6.32.9 kernel source of V10X update for LG-P500,
with optimizations and patches from @DerCaveman, @mik9, @fserve, @franciscofranco and @thachtunganh.