Update template config.h with #pragma once (qmk#3415)

* Update template config.h with `#pragma once`

Making sure this is consistent with qmk#3404

* Move to `#pragma once` for the other templates

Author: evantravers

quantum/template/avr/config.h

@@ -15,10 +15,7 @@ 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 CONFIG_H
-#define CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 /* USB Device descriptor parameter */
 #define VENDOR_ID       0xFEED
@@ -215,4 +212,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 */ 
 
-#endif

quantum/template/base/keymaps/default/config.h

@@ -14,11 +14,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef CONFIG_USER_H
-#define CONFIG_USER_H
-
-#include "config_common.h"
+#pragma once
 
 // place overrides here
-
-#endif

quantum/template/ps2avrgb/config.h

@@ -15,10 +15,7 @@ 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 CONFIG_H
-#define CONFIG_H
-
-#include "config_common.h"
+#pragma once
 
 #define VENDOR_ID       0x20A0
 #define PRODUCT_ID      0x422D
@@ -45,5 +42,3 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 /* key combination for command */
 #define IS_COMMAND() (keyboard_report->mods == (MOD_BIT(KC_LSHIFT) | MOD_BIT(KC_RSHIFT)))
-
-#endif