systemd: bump version to v218

Trivial changes:
- Bump version to v218
- Update the hash file

Non-trivial changes:
- Remove upstreamed patch

  The patch was added by this upstream commit:
  http://cgit.freedesktop.org/systemd/systemd/commit/?id=e6c019026b8cfd27a997e6e6ed1349f8f289b7e2

- Remove non-existent configure options

  --with-firmware-path option was removed by this upstream commit:
  http://cgit.freedesktop.org/systemd/systemd/commit/?id=be2ea723b1d023b3d385d3b791ee4607cbfb20ca

  --disable-tcpwrap option was removed by this upstream commit:
  http://cgit.freedesktop.org/systemd/systemd/commit/?id=7f8aa67131cfc03ddcbd31c0420754864fc122f0

- Select a required dependency

  libmount dependency was added by this upstream commit:
  http://cgit.freedesktop.org/systemd/systemd/commit/?id=8d3ae2bd4c9bf9fc2e57f7b3776325a1c750ca30



  The error for not satisfying this required dependency looks like this:

  checking for MOUNT... no
  configure: error: *** libmount support required but libraries not
    found

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>