Keyboard: Refactor lets split to use split common code (#4536)

* Refactor lets split to use split common code

* Refactor lets split to use split common code

* Build fixes for OLED_sample keymap

* Build fixes for OLED_sample keymap - attempt to reduce firmware size

keyboards/lets_split/rev1/config.h

@@ -16,10 +16,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef REV1_CONFIG_H
-#define REV1_CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xFEED
@@ -80,5 +77,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
-
-#endif

keyboards/lets_split/rev1/rev1.h

@@ -1,5 +1,4 @@
-#ifndef REV1_H
-#define REV1_H
+#pragma once
 
 #include "lets_split.h"
 
@@ -26,5 +25,3 @@
 	}
 
 #define LAYOUT_ortho_4x12 LAYOUT
-
-#endif