LU-9679 modules: Use LIST_HEAD for declaring list_heads

LU-9679 modules: Use LIST_HEAD for declaring list_heads

Rather than
  struct list_head foo = LIST_HEAD_INIT(foo);
use
  LIST_HEAD(foo);

This is shorter and more in-keeping with upstream style.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I36aa8c7e0763f3dfc88fe482cd28935184c1effa
Reviewed-on: https://review.whamcloud.com/36669
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>