Revert "image-fdt: boot_get_fdt() return value when no DTB exists"

It has been found that this change breaks the case of an appended device
tree file, so for the problem in question some other solution must be
found.

This reverts commit c6150aaf2f.

Reported-by: Bill Pringlemeir <bpringlemeir@nbsps.com>
Reported-by: Pantelis Antoniou <panto@antoniou-consulting.com>
Confirmed-by: Bill Pringlemeir <bpringlemeir@nbsps.com>
Signed-off-by: Tom Rini <trini@ti.com>

common/image-fdt.c

@@ -413,11 +413,11 @@ int boot_get_fdt(int flag, int argc, char * const argv[], uint8_t arch,
 			}
 		} else {
 			debug("## No Flattened Device Tree\n");
-			goto error;
+			return 0;
 		}
 	} else {
 		debug("## No Flattened Device Tree\n");
-		goto error;
+		return 0;
 	}
 
 	*of_flat_tree = fdt_blob;