zephyr: 96b_carbon: use flash defines from DTS

Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
diff --git a/boot/zephyr/targets/96b_carbon.h b/boot/zephyr/targets/96b_carbon.h
index 8f52f54..b61cebf 100644
--- a/boot/zephyr/targets/96b_carbon.h
+++ b/boot/zephyr/targets/96b_carbon.h
@@ -26,13 +26,10 @@
 #define FLASH_DRIVER_NAME		CONFIG_SOC_FLASH_STM32_DEV_NAME
 #endif
 #define FLASH_ALIGN			1
-#define FLASH_AREA_IMAGE_0_OFFSET	0x20000
-#define FLASH_AREA_IMAGE_0_SIZE		0x20000
-#define FLASH_AREA_IMAGE_1_OFFSET	0x40000
-#define FLASH_AREA_IMAGE_1_SIZE		0x20000
-#define FLASH_AREA_IMAGE_SCRATCH_OFFSET	0x60000
-#define FLASH_AREA_IMAGE_SCRATCH_SIZE	0x20000
 
-/* Though sectors have variable size on this part, we've chosen
- * three sectors with uniform size here. */
+/*
+ * Though sectors have variable size on this part, we require Zephyr
+ * to choose image and flash sectors with uniform size, each one
+ * sector in size.
+ */
 #define FLASH_AREA_IMAGE_SECTOR_SIZE	0x20000