fs: dlm: add check if dlm is currently running

fs: dlm: add check if dlm is currently running

[ Upstream commit 517461630d1c25ee4dfc1dee80973a64189d6ccf ]

This patch adds checks for dlm config attributes regarding to protocol
parameters as it makes only sense to change them when dlm is not running.
It also adds a check for valid protocol specifiers and return invalid
argument if they are not supported.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>