Fix multiple definition errors for trackball "boards" with no keys (#16350)

keyboards/handwired/aball/aball.c

@@ -15,4 +15,3 @@
  */
 
 #include "aball.h"
-const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = { };

keyboards/handwired/aball/aball.h

@@ -18,12 +18,4 @@
 
 #include "quantum.h"
 
-/* This is a shortcut to help you visually see your layout.
- *
- * The first section contains all of the arguments representing the physical
- * layout of the board and position of the keys.
- *
- * The second converts the arguments into a two-dimensional array which
- * represents the switch matrix.
- */
-#define LAYOUT(k00) {{ KC_NO }}
+#define LAYOUT(k00) {{ k00 }}

keyboards/handwired/aball/keymaps/default/keymap.c

@@ -15,4 +15,5 @@
  */
 #include QMK_KEYBOARD_H
 
-
+// Dummy
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {{ KC_NO }};