kmemleak: Fix the kmemleak tracking of the percpu areas with !SMP

Kmemleak tracks the percpu allocations via a specific API and the
originally allocated areas must be removed from kmemleak (via
kmemleak_free). The code was already doing this for SMP systems.
Reported-by: Sami Liedes <sami.liedes@iki.fi>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

mm/percpu.c

@@ -1895,6 +1895,8 @@ void __init setup_per_cpu_areas(void)
 	fc = __alloc_bootmem(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
 	if (!ai || !fc)
 		panic("Failed to allocate memory for percpu areas.");
+	/* kmemleak tracks the percpu allocations separately */
+	kmemleak_free(fc);
 
 	ai->dyn_size = unit_size;
 	ai->unit_size = unit_size;