Node affine memblock allocation logic is currently implemented across
memblock_alloc_nid() and memblock_alloc_nid_region().  This
reorganizes it such that it resembles that of non-NUMA allocation API.

Area finding is collected and moved into new exported function
memblock_find_in_range_node() which is symmetrical to non-NUMA
counterpart - it handles @start/@end and understands ANYWHERE and
ACCESSIBLE.  memblock_alloc_nid() now simply calls
memblock_find_in_range_node() and reserves the returned area.

This makes memblock_alloc[_try]_nid() observe ACCESSIBLE limit on node
affine allocations too (again, this doesn't make any difference for
the current sole user - sparc64).
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1310460395-30913-8-git-send-email-tj@kernel.org
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>