serial: 8250_pci: handle FL_NOIRQ board flag

serial: 8250_pci: handle FL_NOIRQ board flag

In commit 55f29b748051 ("serial: 8250_pci: Implement MSI(-X) support")
the way the irq gets allocated was changed. With that change the
handling FL_NOIRQ got lost. Restore the old behaviour.

Fixes: 55f29b748051 ("serial: 8250_pci: Implement MSI(-X) support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Link: https://lore.kernel.org/r/20210527095529.26281-1-christian.gmeiner@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>