hvc/xen: fix error path in xen_hvc_init() to always register frontend driver
The xen_hvc_init() function should always register the frontend driver, even when there's no primary console — as there may be secondary consoles. (Qemu can always add secondary consoles, but only the toolstack can add the primary because it's special.) Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231020161529.355083-3-dwmw2@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>