Input: elants_i2c - extend the calibration timeout to 12 seconds

The 23 inch device found in Chrome project buddy requires 9.2~10.5 seconds
to complete calibration. Let's increase calibration timeout to 12 seconds
to give the device enough time.

Signed-off-by: James Chen <james.chen@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>