zephyr: switch to recent defines and include headers

In zephyr code-base some generic include patches
and defines had been deprecated since a while.
This condition was maintained until zephyr v2.1.0 inclusive.

Recently these deprecated items were removed completely from
the zephyr master branch. Zephyr current SHA of this patch is
e124c1cd34938f02bbe879533c6bd29b5ff53707

This patch switch mcuboot to using most recent items.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
diff --git a/boot/zephyr/include/target.h b/boot/zephyr/include/target.h
index f156c32..57a412b 100644
--- a/boot/zephyr/include/target.h
+++ b/boot/zephyr/include/target.h
@@ -31,12 +31,12 @@
 #if (!defined(CONFIG_XTENSA) && !defined(DT_FLASH_DEV_NAME)) || \
     (defined(CONFIG_XTENSA) && !defined(DT_JEDEC_SPI_NOR_0_LABEL)) || \
     !defined(FLASH_ALIGN) ||                  \
-    !defined(FLASH_AREA_IMAGE_0_OFFSET) || \
-    !defined(FLASH_AREA_IMAGE_0_SIZE) || \
-    !defined(FLASH_AREA_IMAGE_1_OFFSET) || \
-    !defined(FLASH_AREA_IMAGE_1_SIZE) || \
-    (!defined(CONFIG_BOOT_SWAP_USING_MOVE) && !defined(FLASH_AREA_IMAGE_SCRATCH_OFFSET)) || \
-    (!defined(CONFIG_BOOT_SWAP_USING_MOVE) && !defined(FLASH_AREA_IMAGE_SCRATCH_SIZE))
+    !defined(DT_FLASH_AREA_IMAGE_0_OFFSET) || \
+    !defined(DT_FLASH_AREA_IMAGE_0_SIZE) || \
+    !defined(DT_FLASH_AREA_IMAGE_1_OFFSET) || \
+    !defined(DT_FLASH_AREA_IMAGE_1_SIZE) || \
+    (!defined(CONFIG_BOOT_SWAP_USING_MOVE) && !defined(DT_FLASH_AREA_IMAGE_SCRATCH_OFFSET)) || \
+    (!defined(CONFIG_BOOT_SWAP_USING_MOVE) && !defined(DT_FLASH_AREA_IMAGE_SCRATCH_SIZE))
 #error "Target support is incomplete; cannot build mcuboot."
 #endif