mm/memblock.c: call kmemleak directly from memblock_(alloc|free)

mm/memblock.c: call kmemleak directly from memblock_(alloc|free)

Kmemleak could ignore memory blocks allocated via memblock_alloc() leading
to false positives during scanning.  This patch adds the corresponding
callbacks and removes kmemleak_free_* calls in mm/nobootmem.c to avoid
duplication.  The kmemleak_alloc() in mm/nobootmem.c is kept since
__alloc_memory_core_early() does not use memblock_alloc() directly.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>