Apply #pragma once, misc cleanup (#12322)

* Apply #pragma once in headers
* Adjust some thermistors formatting
* Misc cleanup and formatting

Marlin/src/HAL/HAL_AVR/fastio_1280.h

@@ -19,6 +19,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+#pragma once
 
 /**
  * Pin mapping for the 1280 and 2560
@@ -28,9 +29,6 @@
  *   Logical Pin   : 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx
  */
 
-#ifndef _FASTIO_1280_H_
-#define _FASTIO_1280_H_
-
 #include "fastio_AVR.h"
 
 // change for your board
@@ -1111,5 +1109,3 @@
 #define PL7_WPORT   PORTL
 #define PL7_DDR     DDRL
 #define PL7_PWM     NULL
-
-#endif // _FASTIO_1280_H_