irqchip/renesas-intc-irqpin: Use of_device_get_match_data() helper

Use the of_device_get_match_data() helper instead of open coding.

Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>