touchscreen: Allow bar tag touchregions to be labeled
This is necessary if you want to detect touches on the bar region
using %Tl conditionals. Suppressing the auto-created region and then
creating one manually using %T doesn't give exactly the same results
because user-defined touch regions can't yet specify padding.
Change-Id: I2f4bde8eb56ba89645c72f3cc9d4b2355b934abd