LU-9859 lod: use linux kernel bitmap API

LU-9859 lod: use linux kernel bitmap API

Now that modern Linux kernels support a bitmap API we can move
away from the libcfs specific bitmap API. This patch changes
the last bitmap in the lod module to use the Linux kernel
bitmap API.

Change-Id: I92c494bf2af62e31d7b9527b3f44580322e48fd3
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/39876
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Oleg Drokin <green@whamcloud.com>