load_multiboot(): get_image_size() returns int
Do not store return of get_image_size() in a uint32_t as it makes it
impossible to detect error returns from get_image_size.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>