Add include guards to some headers

Marlin/src/HAL/HAL_DUE/G2_PWM.h

Marlin/src/HAL/HAL_DUE/SanityCheck.h

Marlin/src/HAL/HAL_ESP32/FlushableHardwareSerial.h

Marlin/src/HAL/HAL_ESP32/SanityCheck.h

Marlin/src/HAL/HAL_ESP32/servotimers.h

Marlin/src/HAL/HAL_LINUX/SanityCheck.h

Marlin/src/HAL/HAL_LPC1768/HAL_Servo_LPC1768.h

Marlin/src/HAL/HAL_LPC1768/SanityCheck.h

Marlin/src/HAL/HAL_LPC1768/include/SPI.h

Marlin/src/HAL/HAL_LPC1768/persistent_store_api.h

Marlin/src/HAL/HAL_LPC1768/u8g/HAL_LCD_I2C_routines.h

Marlin/src/HAL/HAL_LPC1768/u8g/HAL_LCD_defines.h

Marlin/src/HAL/HAL_LPC1768/u8g/HAL_LCD_delay.h

Marlin/src/HAL/HAL_LPC1768/u8g/HAL_LCD_pin_routines.h

Marlin/src/HAL/HAL_STM32F1/SanityCheck.h

Marlin/src/HAL/HAL_STM32F4/SanityCheck.h

Marlin/src/HAL/HAL_STM32F7/SanityCheck.h

Marlin/src/HAL/HAL_TEENSY31_32/HAL_Servo_Teensy.h

Marlin/src/HAL/HAL_TEENSY31_32/HAL_timers_Teensy.h

Marlin/src/HAL/HAL_TEENSY31_32/SanityCheck.h