Refactored the GPIO matrix kscan driver so that only the data and config
structures are defined in the foreach macro. Functionality is unchanged
except for the addition of DT properties to adjust polling speed.
This should make it easier to add other enhancements later, like
improved and customizable debounce behavior.
* Add easier macros for conditional polling/interrupt code.
* Properly continue polling on intervals, without extra
enable/disable code for pins that is superfluous when not trying to
deal with interupts firing.
* Fix to allow multiple GPIO drivers when doing splits w/ IO expanders
