irqchip: crossbar: Remove IS_ERR_VALUE check

IS_ERR_VALUE makes sense only *if* there could be valid values in
negative error range. But in the cases that we do use it, there is no
such case. Just remove the same.

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/1403766634-18543-7-git-send-email-r.sricharan@ti.com


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