Use Flash-based EEPROM on SKR mini-E3 (#15126)

Marlin/src/pins/stm32/pins_BIGTREE_SKR_MINI_E3.h

@@ -33,6 +33,12 @@
 // Ignore temp readings during development.
 //#define BOGUS_TEMPERATURE_GRACE_PERIOD 2000
 
+#define FLASH_EEPROM_EMULATION
+#define EEPROM_PAGE_SIZE     uint16(0x800) // 2KB
+#define EEPROM_START_ADDRESS uint32(0x8000000 + 256 * 1024 - 2 * EEPROM_PAGE_SIZE)
+#undef E2END
+#define E2END                (EEPROM_PAGE_SIZE - 1) // 2KB
+
 //
 // Servos
 //