Revert "mxgrub: Log to ttyS0 as well"

This reverts commit 17202cf.

The kernel doesn't support logging to multiple serial consoles at the
same time.

mxgrub/mxgrub

@@ -248,7 +248,7 @@ sub update_grub_cfg {
 
 	for my $label (@MARIUX) {
 		my $image=label_to_image($label);
-		$kernellist.="\tmenuentry \"$label\" --unrestricted { save_env chosen ; linux /boot/$image crashkernel=256M root=LABEL=root ro console=ttyS0,115200n8 console=ttyS1,115200n8 console=tty0 init=/bin/systemd audit=0 ; initrd /boot/grub/initramfs.igz }\n";
+		$kernellist.="\tmenuentry \"$label\" --unrestricted { save_env chosen ; linux /boot/$image crashkernel=256M root=LABEL=root ro console=ttyS1,115200n8 console=tty0 init=/bin/systemd audit=0 ; initrd /boot/grub/initramfs.igz }\n";
 	}
 
 	my $GRUB_CFG_NEW=<<"EOF";