Keyboard: Crkbd: move I2C and Serial defines to keyboard's config.h (#3970)

* Crkbd: move I2C and Serial defines to keyboard's config.h

per @drashna on Discord

* Crkbd: remove misleading comment re: I2C and Serial

USE_I2C and USE_SERIAL are usually a "one or the other"-type deal, but this keyboard uses both.

keyboards/crkbd/config.h

@@ -21,6 +21,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "config_common.h"
 #include <serial_config.h>
 
+#define USE_I2C
+#define USE_SERIAL
+
 #ifdef USE_Link_Time_Optimization
   // LTO has issues with macros (action_get_macro) and "functions" (fn_actions),
   //  so just disable them

keyboards/crkbd/keymaps/default/config.h

@@ -20,10 +20,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #pragma once
 
-/* Use I2C or Serial */
-
-#define USE_I2C
-#define USE_SERIAL
 //#define USE_MATRIX_I2C
 
 /* Select hand configuration */

keyboards/crkbd/keymaps/like_jis/config.h

@@ -20,10 +20,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #pragma once
 
-/* Use I2C or Serial */
-
-#define USE_I2C
-#define USE_SERIAL
 //#define USE_MATRIX_I2C
 
 /* Select hand configuration */