Use MARLIN_EEPROM_SIZE with E2END as fallback (#18059)

Marlin/src/HAL/TEENSY31_32/eeprom.cpp

@@ -28,8 +28,14 @@
  */
 
 #include "../shared/eeprom_api.h"
+#include <avr/eeprom.h>
 
-bool PersistentStore::access_start() { return true; }
+#ifndef MARLIN_EEPROM_SIZE
+  #define MARLIN_EEPROM_SIZE size_t(E2END + 1)
+#endif
+size_t PersistentStore::capacity() { return MARLIN_EEPROM_SIZE; }
+
+bool PersistentStore::access_start()  { return true; }
 bool PersistentStore::access_finish() { return true; }
 
 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {