input: atmel-mxt-ts: Provide max touch coordinates via platform data

The atmel_mxt_ts driver manipulates the touch coordinates
if they are < 1024. In cases when the display < 1024 and
virtual key area > 1024, there is a problem in reporting
the coordinates for the virtual key area. Add new pdata
variables which can handle this.

Change-Id: Ic31db032a1598c60c01bff31c7b36042f42c9817
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>