Add a missing #pragma once

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

src/Kaleidoscope/EEPROM-Keymap.h

@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#pragma once
+
 #include <Kaleidoscope.h>
 #include <Kaleidoscope-EEPROM-Settings.h>