libhugetlbfs: use ARCH ppc/ppc64 for powerpc/powerpc64

In recent libhugetlbfs source, powerpc/powerpc64 is changed back to
ppc/ppc64 (to match with the output of `uname -a`).

Update the recipe to avoid build issue for now.

Signed-off-by: Ting Liu <b28495@freescale.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>