powerpc/mm: fix a hardcode on memory boundary checking

[Michael Ellerman]

On Thu, 2017-01-12 at 09:09:06 UTC, Rui Teng wrote:
> The offset of hugepage block will not be 16G, if the expected
> page is more than one. Calculate the totol size instead of the
> hardcode value.
> 
> Signed-off-by: Rui Teng <rui.teng at linux.vnet.ibm.com>
> Tested-by: Anshuman Khandual <khandual at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/23493c121912a39f0262e0dbeb236e

cheers