STM32 EEPROM Emulation (#3741)

* STM32 EEPROM Emulation

- Added EEPROM emulation libaries from libmaple and Arduino_STM32. https://github.com/rogerclarkmelbourne/Arduino_STM32 and https://github.com/leaflabs/libmaple.
- Renamed teensy EEPROM library and added conditional selection of library.
- Remapped EEPROM memory map for 16 byte blocks (as is with STM32f3xx MCUs).
- Added EEPROM initialization in main.c of Chibios.
- Added EEPROM format to clear the emulated pages when EEPROM is marked as invalid.

* Fixed ifdef

tmk_core/common/chibios/flash_stm32.h

@@ -0,0 +1,53 @@
+/*
+ * This software is experimental and a work in progress.
+ * Under no circumstances should these files be used in relation to any critical system(s).
+ * Use of these files is at your own risk.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and 
+ * https://github.com/leaflabs/libmaple
+ *
+ * Modifications for QMK and STM32F303 by Yiancar
+ */
+
+#ifndef __FLASH_STM32_H
+#define __FLASH_STM32_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+#include "ch.h"
+#include "hal.h"
+
+typedef enum
+    {
+    FLASH_BUSY = 1,
+    FLASH_ERROR_PG,
+    FLASH_ERROR_WRP,
+    FLASH_ERROR_OPT,
+    FLASH_COMPLETE,
+    FLASH_TIMEOUT,
+    FLASH_BAD_ADDRESS
+    } FLASH_Status;
+
+#define IS_FLASH_ADDRESS(ADDRESS) (((ADDRESS) >= 0x08000000) && ((ADDRESS) < 0x0807FFFF))
+
+FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout);
+FLASH_Status FLASH_ErasePage(uint32_t Page_Address);
+FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data);
+
+void FLASH_Unlock(void);
+void FLASH_Lock(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __FLASH_STM32_H */