sparc/of: Remove on-stack cpumask var

In general it's preferable to avoid placing cpumasks on the stack, as
for large values of NR_CPUS these can consume significant amounts of
stack space and make stack overflows more likely.

@cpumask of irq_set_affinity() is read-only and free of change, drop
unneeded cpumask var.

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/r/20240424025548.3765250-4-dawei.li@shingroup.cn
Signed-off-by: Andreas Larsson <andreas@gaisler.com>

Author: Dawei Li

arch/sparc/kernel/of_device_64.c

@@ -624,10 +624,7 @@ static unsigned int __init build_one_device_irq(struct platform_device *op,
 out:
 	nid = of_node_to_nid(dp);
 	if (nid != -1) {
-		cpumask_t numa_mask;
-
-		cpumask_copy(&numa_mask, cpumask_of_node(nid));
-		irq_set_affinity(irq, &numa_mask);
+		irq_set_affinity(irq, cpumask_of_node(nid));
 	}
 
 	return irq;