modules: Don't allocate space for non-allocable sections

modules: Don't allocate space for non-allocable sections

Currently when loading GRUB modules we allocate space for all sections
including those without SHF_ALLOC set. We then copy the sections that
/do/ have SHF_ALLOC set into the allocated memory leaving some of our
allocation untouched forever. Additionally, on platforms with GOT fixups
and trampolines we currently compute alignment round-ups for the
sections and sections with sh_size = 0. This patch removes the extra
space from the allocation computation and makes the allocation
computation loop skip empty sections as the loading loop does.

Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-By: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>