exfat: Fix symlink generation

 * Don't require inclusion of a separate package for symlinks.  The
   symlinks should always be present if the main package builds.
 * Don't depend on anything for symlink targets.

Change-Id: Ida6e2f1840f8c011e9764da38b26e2b349682f85
exfat: Compilation fixes on L

Change-Id: I8cc578bab0a37a3e2901f4e6c41ad805059c92a5