of/irq: Use irq_of_parse_and_map()

Replace some instances of of_irq_map_one()/irq_create_of_mapping() and
of_irq_to_resource() by the simpler equivalent irq_of_parse_and_map().

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
[grant.likely: resolved conflicts with core code renames]
Signed-off-by: Grant Likely <grant.likely@linaro.org>