LU-2800 autoconf: remove LC_INVALIDATE_BDEV_2ARG test

LU-2800 autoconf: remove LC_INVALIDATE_BDEV_2ARG test

invalidate_bdev has taken one argument since v2.6.22
We can remove the test and the dead code.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Change-Id: I535f1cbe1c46fb5c98d5de046b85eb8365084d7b
Reviewed-on: http://review.whamcloud.com/5345
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>