ld: Always call output_unknown_cmdline_warning

Call output_unknown_cmdline_warning if there are no input files so that

$ ld -z bad-option

reports

ld: warning: -z bad-option ignored
ld: no input files

instead of

ld: no input files

	PR ld/31289
	* ldmain.c (main): Call output_unknown_cmdline_warning if there
	are no input files.
diff --git a/ld/ldmain.c b/ld/ldmain.c
index 3b4ad14..9ae541a 100644
--- a/ld/ldmain.c
+++ b/ld/ldmain.c
@@ -471,6 +471,7 @@
     {
       if (version_printed || command_line.print_output_format)
 	xexit (0);
+      output_unknown_cmdline_warnings ();
       einfo (_("%F%P: no input files\n"));
     }