Fix test failure caused by bad handling of ramdisk

Commit e3a5bbce broke the FIT image tests by not loading a ramdisk even if
a load address is provided in the FIT. The rationale was that a load address
of 0 should be considered to mean 'do not load'.

Add a new load operation which supports this feature, so that the ramdisk
will be loaded if a non-zero load address is provided.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/image-fit.c b/common/image-fit.c
index c61be65..255c4ca 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -1656,7 +1656,7 @@
 			bootstage_error(bootstage_id + BOOTSTAGE_SUB_LOAD);
 			return -EBADF;
 		}
-	} else {
+	} else if (load_op != FIT_LOAD_OPTIONAL_NON_ZERO || load) {
 		ulong image_start, image_end;
 		ulong load_end;
 		void *dst;
diff --git a/common/image.c b/common/image.c
index d4ccff0..38b56e3 100644
--- a/common/image.c
+++ b/common/image.c
@@ -966,7 +966,8 @@
 					&fit_uname_config, arch,
 					IH_TYPE_RAMDISK,
 					BOOTSTAGE_ID_FIT_RD_START,
-					FIT_LOAD_IGNORED, &rd_data, &rd_len);
+					FIT_LOAD_OPTIONAL_NON_ZERO,
+					&rd_data, &rd_len);
 			if (rd_noffset < 0)
 				return 1;
 
diff --git a/include/image.h b/include/image.h
index 69f86ad..3401056 100644
--- a/include/image.h
+++ b/include/image.h
@@ -412,6 +412,7 @@
 enum fit_load_op {
 	FIT_LOAD_IGNORED,	/* Ignore load address */
 	FIT_LOAD_OPTIONAL,	/* Can be provided, but optional */
+	FIT_LOAD_OPTIONAL_NON_ZERO,	/* Optional, a value of 0 is ignored */
 	FIT_LOAD_REQUIRED,	/* Must be provided */
 };