irqchip/gic-v3-its: Fix build for !SMP

Commit 835f442 ("irqchip/gic-v3-its: Limit memreserve cpuhp state
lifetime") added a reference to cpus_booted_once_mask, which does not
exist on !SMP builds, breaking the build for such configurations.

Given the intent of the check, short circuit it to always pass.

Cc: Valentin Schneider <[email protected]>
Fixes: 835f442 ("irqchip/gic-v3-its: Limit memreserve cpuhp state lifetime")
Signed-off-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: ardbiesheuvel

drivers/irqchip/irq-gic-v3-its.c

@@ -5241,7 +5241,8 @@ static int its_cpu_memreserve_lpi(unsigned int cpu)
 
 out:
 	/* Last CPU being brought up gets to issue the cleanup */
-	if (cpumask_equal(&cpus_booted_once_mask, cpu_possible_mask))
+	if (!IS_ENABLED(CONFIG_SMP) ||
+	    cpumask_equal(&cpus_booted_once_mask, cpu_possible_mask))
 		schedule_work(&rdist_memreserve_cpuhp_cleanup_work);
 
 	gic_data_rdist()->flags |= RD_LOCAL_MEMRESERVE_DONE;