tizen: units: add 'smackfsroot=*' option into tmp.mount when SMACK is enabled

tizen: units: add 'smackfsroot=*' option into tmp.mount when SMACK is enabled

If SMACK is enabled, 'smackfsroot=*' option should be specified in
tmp.mount file since many non-root processes use /tmp for temporary
usage. If not, /tmp is labeled as '_' and smack denial occurs when
writing.

Note: The original commit has been dropped upstream and replaced with
SmackFileSystemRoot  option later renamed to SmackFileSystemRootLabel.
Alas the option didn't work properly and has been dropped too.

Change-Id: I11df1ad555f376eaf0588d35e91789c9e2b07f8d
Origin: https://github.com/systemd/systemd/commit/409c2a13fd65692c6
Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>