irqchip: crossbar: Return proper error value

crossbar_of_init always returns -ENOMEM in case of errors.
There can be other causes of failure like invalid data from
DT. So return a appropriate error value for that case.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: https://lkml.kernel.org/r/1403766634-18543-10-git-send-email-r.sricharan@ti.com


Signed-off-by: Jason Cooper <jason@lakedaemon.net>