remove read of flash_size in STM32F2

src/flash/nor/stm32f2xxx.c

@@ -578,15 +578,6 @@ static int stm32x_probe(struct flash_bank *bank)
 		return retval;
 	LOG_INFO("device id = 0x%08" PRIx32 "", device_id);
 
-	/* get flash size from target. */
-	retval = target_read_u16(target, 0x1FFFF7E0, &num_pages);
-	if (retval != ERROR_OK)
-	{
-		LOG_WARNING("failed reading flash size, default to max target family");
-		/* failed reading flash size, default to max target family */
-		num_pages = 0xffff;
-	}
-
 	if ((device_id & 0x7ff) != 0x411)
 	{
 		LOG_WARNING("Cannot identify target as a STM32 family, try the other STM32 drivers.");