STM32F437: remove flash api implementation

STM32F4 already contains generic flash api implementation, use it.

Author: 0xc0170

targets/TARGET_STM/TARGET_STM32F4/TARGET_STM32F437xG/device/flash_api.c

@@ -35,6 +35,10 @@
 
 #if DEVICE_FLASH
 
+#if defined (STM32F427xx) || defined (STM32F437xx)
+#define FLASH_SIZE      (uint32_t) 0x100000
+#endif
+ 
 /* Exported types ------------------------------------------------------------*/
 /* Exported constants --------------------------------------------------------*/
 /* Exported macro ------------------------------------------------------------*/
@@ -53,4 +57,4 @@
 #define ADDR_FLASH_SECTOR_11    ((uint32_t)0x080E0000) /* Base @ of Sector 11, 128 Kbytes */
 
 #endif
-#endif
+#endif