Fix SAMD51 i2c EEPROM (#17815)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/HAL/SAMD51/eeprom_wired.cpp

 #include "../shared/eeprom_api.h"
 
 size_t PersistentStore::capacity()    { return E2END + 1; }
-bool PersistentStore::access_start()  { return true; }
 bool PersistentStore::access_finish() { return true; }
 
+bool PersistentStore::access_start() {
+  eeprom_init();
+  return true;
+}
+
 bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc) {
   while (size--) {
     const uint8_t v = *value;

Marlin/src/HAL/shared/eeprom_if.h

 //
 // EEPROM
 //
+void eeprom_init();
 void eeprom_write_byte(uint8_t *pos, unsigned char value);
 uint8_t eeprom_read_byte(uint8_t *pos);

Marlin/src/HAL/shared/eeprom_if_i2c.cpp

 // Public functions
 // ------------------------
 
-static void eeprom_init() { Wire.begin(); }
+void eeprom_init() { Wire.begin(); }
 
 void eeprom_write_byte(uint8_t *pos, unsigned char value) {
   const unsigned eeprom_address = (unsigned)pos;