"Pick the right alignment default when creating dax devices" failed to build on powerpc

[Qian Cai]

The linux-next commit "libnvdimm/dax: Pick the right alignment default when
creating dax devices" causes powerpc failed to build with this config. Reverted
it fixed the issue.

ERROR: "hash__has_transparent_hugepage" [drivers/nvdimm/libnvdimm.ko] undefined!
ERROR: "radix__has_transparent_hugepage" [drivers/nvdimm/libnvdimm.ko]
undefined!
make[1]: *** [scripts/Makefile.modpost:93: __modpost] Error 1
make: *** [Makefile:1305: modules] Error 2

[1] https://patchwork.kernel.org/patch/11133445/
[2] https://raw.githubusercontent.com/cailca/linux-mm/master/powerpc.config