Devicetree bugfix for v3.18

Single bugfix for boot failure seen in the wild. The memory reserve code
 tries to be clever about reserving the FDT, but it should just go ahead
 and reserve it unconditionally to avoid the problem of partial overlap
 described in the patch.
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Merge tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux

Pull devicetree bugfix from Grant Likely:
 "One more bug fix for v3.18.  I debated whether or not to send you this
  merge request because we're at such a late rc.  The bug isn't critical
  in that there is only one system known to be affected and the patch is
  easy to backport.  The codepath is used by pretty much every DT based
  system, so there is risk a of regression (it /should/ be safe, but
  I've been bitten by stuff that should be safe before).  I've had it in
  linux-next for a week and haven't received any complaints.

  I think it probably should just be merged right away rather than
  waiting for the merge window and backporting.  It does fix a real bug
  and the code is theoretically safer after the change.  I can't think
  of any situation where it would be dangerous to reserve the DT memory
  an extra time.

  Summary from tag:

    Single bugfix for boot failure seen in the wild.  The memory reserve
    code tries to be clever about reserving the FDT, but it should just
    go ahead and reserve it unconditionally to avoid the problem of
    partial overlap described in the patch"

* tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux:
  of/fdt: memblock_reserve /memreserve/ regions in the case of partial overlap

drivers/of/fdt.c

@@ -964,8 +964,6 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
 					phys_addr_t size, bool nomap)
 {
-	if (memblock_is_region_reserved(base, size))
-		return -EBUSY;
 	if (nomap)
 		return memblock_remove(base, size);
 	return memblock_reserve(base, size);