tools: dumpimage: Provide more feedback on internal errors

The dumpimage utility errors out in a number of places without providing
sufficient feedback to allow the user to easily determine what has gone
wrong. Add additional error messages to make the cause of the failure
more obvious.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/tools/dumpimage.c b/tools/dumpimage.c
index ee3d41d..d5f893d 100644
--- a/tools/dumpimage.c
+++ b/tools/dumpimage.c
@@ -35,14 +35,23 @@
 	if (tparams->verify_header) {
 		retval = tparams->verify_header((unsigned char *)ptr,
 				sbuf->st_size, &params);
-		if (retval != 0)
+		if (retval != 0) {
+			fprintf(stderr, "%s: failed to verify header of %s\n",
+				params.cmdname, tparams->name);
 			return -1;
+		}
+
 		/*
 		 * Extract the file from the image
 		 * if verify is successful
 		 */
 		if (tparams->extract_subimage) {
 			retval = tparams->extract_subimage(ptr, &params);
+			if (retval != 0) {
+				fprintf(stderr, "%s: extract_subimage failed for %s\n",
+					params.cmdname, tparams->name);
+				return -3;
+			}
 		} else {
 			fprintf(stderr,
 				"%s: extract_subimage undefined for %s\n",
@@ -175,6 +184,9 @@
 		 * image type. Returns the error code if not matched
 		 */
 		retval = dumpimage_extract_subimage(tparams, ptr, &sbuf);
+		if (retval)
+			fprintf(stderr, "%s: Can't extract subimage from %s\n",
+				params.cmdname, params.imagefile);
 	} else {
 		/*
 		 * Print the image information for matched image type