n_gsm.c : More cleanup to fullfill Linux 3.0 API

n_gsm.c : More cleanup to fullfill Linux 3.0 API

BZ: 21896

- Struct file *filp in tiocmget and tiocmset are not nedded anymore.
- Need to cast dummy file * with correct type.

Change-Id: I63c1b36c065c92509fe957e107cee2666386d646
Signed-off-by: Vincent Pillet <vincentx.pillet@intel.com>
Reviewed-on: http://android.intel.com:8080/33515
Reviewed-by: Guerard, Christophe <christophe.guerard@intel.com>
Reviewed-by: Predon, Frederic <frederic.predon@intel.com>
Reviewed-by: Robert, Denis <denis.robert@intel.com>
Reviewed-by: Lebsir, SamiX <samix.lebsir@intel.com>
Tested-by: Lebsir, SamiX <samix.lebsir@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>