boot : Adding encrypted ram-load support

This patch adds the possibility to boot using ram-load with an
encrypted image. This is enabled when both the flags MCUBOOT_RAM_LOAD
and MCUBOOT_ENC_IMAGES are defined.

Signed-off-by: Fabio Utzig <utzig@apache.org>
Signed-off-by: Hugo L'Hostis <hugo.lhostis@arm.com>
Signed-off-by: Salome Thirot <salome.thirot@arm.com>
Change-Id: I7756c2c634d90a2e726117d6cfc5650653cf1b51
diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index c730052..67be5eb 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -143,9 +143,9 @@
 #else
 #define ARE_SLOTS_EQUIVALENT()    1
 
-#ifdef MCUBOOT_ENC_IMAGES
-#error "Image encryption (MCUBOOT_ENC_IMAGES) is not supported when MCUBOOT_DIRECT_XIP or MCUBOOT_RAM_LOAD mode is selected."
-#endif
+#if defined(MCUBOOT_DIRECT_XIP) && defined(MCUBOOT_ENC_IMAGES)
+#error "Image encryption (MCUBOOT_ENC_IMAGES) is not supported when MCUBOOT_DIRECT_XIP is selected."
+#endif /* MCUBOOT_DIRECT_XIP && MCUBOOT_ENC_IMAGES */
 #endif /* MCUBOOT_DIRECT_XIP || MCUBOOT_RAM_LOAD */
 
 #define BOOT_MAX_IMG_SECTORS       MCUBOOT_MAX_IMG_SECTORS