cifs: print server capabilities in DebugData

[ Upstream commit 52768695 ]

In the output of /proc/fs/cifs/DebugData, we do not
print the server->capabilities field today.
With this change, we will do that.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>