In case of failures brcmuart_probe() always returned -ENODEV, this
isn't correct for example platform_get_irq_byname() may return
-EPROBE_DEFER to handle such cases propagate error codes in
brcmuart_probe() in case of failures.
Fixes: 41a469482de25 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>