padata: Fix cpu hotplug

We don't remove the cpu that went offline from our cpumasks
on cpu hotplug. This got lost somewhere along the line, so
restore it. This fixes a hang of the padata instance on cpu
hotplug.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/kernel/padata.c b/kernel/padata.c
index de3d0d9..89fe3d1 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -748,6 +748,9 @@
 			return -ENOMEM;
 
 		padata_replace(pinst, pd);
+
+		cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
+		cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
 	}
 
 	return 0;