watchdog/wdt-main: Use cpumask_of() to avoid cpumask var on stack

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.

Use cpumask_of() to avoid the need for a temporary cpumask on the stack

Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/TYTP286MB3564B037A81DAAE1AC3A16F3CA062@TYTP286MB3564.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Author: Dawei Li

drivers/watchdog/octeon-wdt-main.c

@@ -381,11 +381,7 @@ static int octeon_wdt_cpu_online(unsigned int cpu)
 
 	/* Must set the irq affinity here */
 	if (octeon_has_feature(OCTEON_FEATURE_CIU3)) {
-		cpumask_t mask;
-
-		cpumask_clear(&mask);
-		cpumask_set_cpu(cpu, &mask);
-		irq_set_affinity(irq, &mask);
+		irq_set_affinity(irq, cpumask_of(cpu));
 	}
 
 	cpumask_set_cpu(cpu, &irq_enabled_cpus);