powerpc/smp: Remove unnecessary variable

Commit 3ab33d6d ("powerpc/smp: Optimize update_mask_by_l2")
introduced submask_fn in update_mask_by_l2 to track the right submask.
However commit f6606cfd ("powerpc/smp: Dont assume l2-cache to be
superset of sibling") introduced sibling_mask in update_mask_by_l2 to
track the same submask. Remove sibling_mask in favour of submask_fn.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201019042716.106234-2-srikar@linux.vnet.ibm.com

arch/powerpc/kernel/smp.c

@@ -1247,18 +1247,16 @@ static bool update_mask_by_l2(int cpu)
 	cpumask_var_t mask;
 	int i;
 
+	if (has_big_cores)
+		submask_fn = cpu_smallcore_mask;
+
 	l2_cache = cpu_to_l2cache(cpu);
 	if (!l2_cache) {
-		struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
-
 		/*
 		 * If no l2cache for this CPU, assume all siblings to share
 		 * cache with this CPU.
 		 */
-		if (has_big_cores)
-			sibling_mask = cpu_smallcore_mask;
-
-		for_each_cpu(i, sibling_mask(cpu))
+		for_each_cpu(i, submask_fn(cpu))
 			set_cpus_related(cpu, i, cpu_l2_cache_mask);
 
 		return false;
@@ -1267,9 +1265,6 @@ static bool update_mask_by_l2(int cpu)
 	alloc_cpumask_var_node(&mask, GFP_KERNEL, cpu_to_node(cpu));
 	cpumask_and(mask, cpu_online_mask, cpu_cpu_mask(cpu));
 
-	if (has_big_cores)
-		submask_fn = cpu_smallcore_mask;
-
 	/* Update l2-cache mask with all the CPUs that are part of submask */
 	or_cpumasks_related(cpu, cpu, submask_fn, cpu_l2_cache_mask);