refactor(kscan): Demacroify GPIO matrix driver

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.

app/drivers/zephyr/dts/bindings/kscan/zmk,kscan-gpio-matrix.yaml

@@ -17,6 +17,11 @@ properties:
   debounce-period:
     type: int
     default: 5
+    description: Debounce time in milliseconds
+  poll-period-ms:
+    type: int
+    default: 10
+    description: Time between reads in milliseconds when polling is enabled
   diode-direction:
     type: string
     default: row2col