serial: cpm_uart: Don't request IRQ too early for console port

serial: cpm_uart: Don't request IRQ too early for console port

The following message is seen during boot and the activation of
console port gets delayed until normal serial ports activation.

[    0.001346] irq: no irq domain found for pic@930 !

The console port doesn't need irq, perform irq reservation later,
during cpm_uart probe.

While at it, don't use NO_IRQ but 0 which is the value returned
by irq_of_parse_and_map() in case of error. By chance powerpc's
NO_IRQ has value 0 but on some architectures it is -1.

Fixes: 14d893fc6846 ("powerpc/8xx: Convert CPM1 interrupt controller to platform_device")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/8bed0f30c2e9ef16ae64fb1243a16d54a48eb8da.1664526717.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>