irqchip: gic-v3: Use of_cpu_node_to_id helper

Use the new generic helper of_cpu_node_to_id() instead
of using our own version to map a device node to logical CPU
number.

Change-Id: I85dfbe98e4a4d9f5630d3bcf78de06517e2146b7
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: c08ec7da75f393c0dbaba9455f4f6b2a5e709355
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>