irqchip/gic-v3: Iterate over possible CPUs by for_each_possible_cpu()

get_cpu_number() doesn't use existing helper to iterate over possible
CPUs, It will cause an error in case of discontinuous @cpu_possible_mask
such as 0b11110001, which can result from a core having failed to come
up on a SMP machine.

Fixed by using existing helper for_each_possible_cpu().
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-gic-v3.c

@@ -1042,7 +1042,7 @@ static int get_cpu_number(struct device_node *dn)
 {
 	const __be32 *cell;
 	u64 hwid;
-	int i;
+	int cpu;
 
 	cell = of_get_property(dn, "reg", NULL);
 	if (!cell)
@@ -1056,9 +1056,9 @@ static int get_cpu_number(struct device_node *dn)
 	if (hwid & ~MPIDR_HWID_BITMASK)
 		return -1;
 
-	for (i = 0; i < num_possible_cpus(); i++)
-		if (cpu_logical_map(i) == hwid)
-			return i;
+	for_each_possible_cpu(cpu)
+		if (cpu_logical_map(cpu) == hwid)
+			return cpu;
 
 	return -1;
 }