percpu: free percpu allocation info for uniprocessor system

commit 3189eddb upstream.

Currently, only SMP system free the percpu allocation info.
Uniprocessor system should free it too. For example, one x86 UML
virtual machine with 256MB memory, UML kernel wastes one page memory.
Signed-off-by: Honggang Li <enjoymindful@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

mm/percpu.c

@@ -1911,6 +1911,8 @@ void __init setup_per_cpu_areas(void)
 
 	if (pcpu_setup_first_chunk(ai, fc) < 0)
 		panic("Failed to initialize percpu areas.");
+
+	pcpu_free_alloc_info(ai);
 }
 
 #endif	/* CONFIG_SMP */