libhugetlbfs: Fix page size & text offset for arm arches

Fixed computation of page size and text segment offset for various arm
architectures - including both LE and BE variants of armv7 as well as
aarch64

Upstream Status: Accepted at libhugetlbfs project

Signed-off-by: Gary S. Robertson <gary.robertson@linaro.org>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>