loader.efi: disable workaround for serial console on non-x86

As efi console is drawn and with functional comconsole driver,
we can use proper terminal emulator on efi framebuffer console.

stand/efi/libefi/efi_console.c

@@ -929,7 +929,11 @@ cons_update_mode(bool use_gfx_mode)
 	 * also just use the old emulator. RB_MULTIPLE also implies
 	 * we're using a serial console.
 	 */
+#if defined(__i386__) || defined(__amd64__)
 	mode = parse_uefi_con_out();
+#else
+	mode = 0;
+#endif
 	if ((mode & (RB_SERIAL | RB_MULTIPLE)) == 0) {
 		conout->EnableCursor(conout, FALSE);
 		gfx_state.tg_cursor_visible = false;