move module list creation outside conditionals

Currently the two special-case calls to create just a module load list
(as opposed to copying a set of modules and creating a module load list)
are inside checks that the related board macro for the module set is not
empty.

While it would be incorrect to create a non-empty module load list with
an empty set of modules, this error would quickly surface at runtime.
More importantly, moving these out will permit refactoring this code to
clean it up.

Bug: 157645635
Change-Id: I199788d49072d4c59737b3ef2c75546852cf3e36
Merged-In: I199788d49072d4c59737b3ef2c75546852cf3e36