input: touch: synaptics: Optionally reset the device when blanking display

This re-introduces e1786f2ab98c5d1062b33959ebd9523609c9468f - this
time for all find7-variants, but depending on the newly introduced
sysfs attibute "reset_on_suspend" (0/off by default).

To activate it, use:
echo 1 > /sys/class/input/inputX/reset_on_suspend

Apparently, all find7-variants still have big touchscreen problems
despite OPPO's driver updates (including svn9954), see e.g.
http://www.oppoforums.com/search/15887105/?q=touchscreen and
e.g. https://jira.cyanogenmod.org/browse/BACON-55.

This "recovery mechanism" (as RC called it), of course, does not fix
the problem, but it might be better than rebooting the phone every
time the display gets warm and unresponsive. On the downside, if it
works not just for me, we might never get a real fix.

Change-Id: Ief6214f687562746bd1b7b3f8a4b30d099a698f0