mpc832x_rdb: fix of_irq_to_resource() error check

[Michael Ellerman]

On Sat, 2017-07-29 at 19:52:09 UTC, Sergei Shtylyov wrote:
> of_irq_to_resource() has recently been  fixed to return negative error #'s
> along with 0 in case of failure,  however the Freescale MPC832x RDB board
> code still only regards 0 as as failure indication -- fix it up.
> 
> Fixes: 7a4228bbff76 ("of: irq: use of_irq_get() in of_irq_to_resource()")
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov at cogentembedded.com>
> Acked-by: Scott Wood <oss at buserror.net>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/f29bb7861a5107cc1afbf5a565c310

cheers