SOLARIS: convert from ancient _depends_on to ELF dependencies

SOLARIS: convert from ancient _depends_on to ELF dependencies

The ancient way of declaring module dependencies with _depends_on has
been deprecated since SunOS 2.6 (circa 1996). The presence of the old
_depends_on symbol triggers a warning message on the console starting
with Solaris 12, and the kernel runtime loader (krtld) feature of using
the _depends_on symbol to load dependencies may be removed in a future
version of Solaris.

Convert the kernel module from the ancient _depends_on method to modern
ELF dependencies.  Remove the old _depends_on symbol and specify the -dy
and -N <name> linker options to set the ELF dependencies at link time,
as recommended in the Solaris device driver developer guidelines [1].

This commit does not change the declared dependencies, which may be
vestiges of ancient afs versions.

[1]: http://docs.oracle.com/cd/E19455-01/805-7378/6j6un037u/index.html#loading-16

Reviewed-on: https://gerrit.openafs.org/12453
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 37db7985fde9e6a5e71ae628d0b7124a27bf31c3)

Change-Id: I1a4ad8bface1ecf774e906b846c2e8263631d77a
Reviewed-on: https://gerrit.openafs.org/12514
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>