irqchip: intc-irqpin: Make use of devm functions

Use devm_kzalloc(), devm_ioremap_nocache()
and devm_request_irq() to simplify error
handling.

Signed-off-by: Magnus Damm <damm@opensource.se>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>