MIPS: ath79: fix WMAC IRQ resource assignment

The '.start' field of the IRQ resource assigned twice
in ar934x_wmac_setup(). The second assignment must
set the '.end' field. Fix it.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/4954/


Signed-off-by: John Crispin <blogic@openwrt.org>