mboot64: fix a couple of bugs in cmd_elf.

...around module handling.

Some problem with LMB a well, ugh, ugh...

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
mboot64: fix annoying bug in LMB.

The annoying bug was that if alignment was not 1, then
the region tested for overlap was different than the region
added if no overlap happened - the region added had size
padded up to align. This is of course a mistake, since
that's not what the region was tested for.

With that fixed, I was left pondering if I should ensure
size is padded up to align, and decided to keep this old
behavior.

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>