serial: 8250: omap: Fix freeing of resources on failed register

If serial8250_register_8250_port() fails, the SoC can hang as the
deferred PMQoS work will still run as is not flushed and removed.

Fixes: 61929cf0

 ("tty: serial: Add 8250-core based omap driver")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230508082014.23083-2-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>