Remove the need to specify NUM_OF_ENCODERS for the Encoder feature (#6328)

* Remove the need to set NUM_OF_ENCODERS

Instead, calculate the size of the array, and use that instead

* Add hack for split common support

* Remove NUM_OF_ENCODERS from keyboard config

Can be reverted, if needed

keyboards/cannonkeys/satisfaction75/config.h

@@ -35,7 +35,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define MATRIX_ROW_PINS { B3, B4, A0, A2, A4, A3 }
 #define DIODE_DIRECTION COL2ROW
 
-#define NUMBER_OF_ENCODERS 1
 #define ENCODERS_PAD_A { B9 }
 #define ENCODERS_PAD_B { B8 }