Albeit a fairly benign change, make sure you have a /system backup you can restore if needed - would be a shame to lose your touchscreen
Using Root Explorer or command line
Replace (yes that means remove this file and exchange with another)
with xml extracted from attached zip.
adb shell chmod 644 /system/etc/permissions/android.hardware.touchscreen.multitouch.distinct.x ml
(rw-r--r-- if you do it via root explorer gui)
Voila... gmaps is a lot more fun
just google "android.hardware.touchscreen.multitouch.disti nct" if you want to feel more comfortable