efi_loader: correctly apply relocations from the .reloc section

efi_loader: correctly apply relocations from the .reloc section

Instead of difference between preferred and actual image base, the
actual base is added to the fields specified in the .reloc section.

Use ImageBase from PE optional header to compute the delta,
exit early if the image is loaded at the preferred address.

Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>