Change keyboard level include guards to pragma once (#14248)

* Change keyboard level include guards to `pragma once`

And clean up a lot of layout macros

* Oops

* Remove dangling endif

keyboards/preonic/rev1/config.h

@@ -15,12 +15,9 @@ 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
+#pragma once
 
 #include "config_common.h"
 
 #define DEVICE_VER      0x0001
 #define PRODUCT_ID      0x67F3
-
-#endif