httpboot: Convert 404 Not found error to EFI_NOT_FOUND

This will result in falling back to the default second stage loader like
disk based lookups.

httpboot.c

@@ -565,7 +565,14 @@ receive_http_response(EFI_HTTP_PROTOCOL *http, VOID **buffer, UINT64 *buf_size)
 	if (http_status != HTTP_STATUS_200_OK) {
 		perror(L"HTTP Status Code: %d\n",
 		       convert_http_status_code(http_status));
-		efi_status = EFI_ABORTED;
+		switch (http_status) {
+		case HTTP_STATUS_404_NOT_FOUND:
+			efi_status = EFI_NOT_FOUND;
+			break;
+		default:
+			efi_status = EFI_ABORTED;
+			break;
+		}
 		goto error;
 	}