LU-9859 libcfs: make signal-blocking functions inline

LU-9859 libcfs: make signal-blocking functions inline

cfs_block_sigsinv() and cfs_restore_sigs() are now
simple enough to inline them.

Linux-commit: 6b7936ceefa7ed1d7c0576ed9660cc6cb90d61df

Change-Id: I36c62a091a9c066573930cfbae9bf65836203516
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-on: https://review.whamcloud.com/38081
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>