Telephony: Handling of supplimentary services in Call

When there are active calls, the candial() returns false
and if the user supplied an MMI code for supplementary
service it will not be accepted.

The codes for supplementary services such as hold, reflect
transfer etc are now handled with this patch, even when
dial cannot be done.

Change-Id: Ic90d71112ca9fd3250b82660a2929590491e41ba
Author: Fabien Hubert <fabien.hubert@intel.com>
Signed-off-by: Fabien Hubert <fabien.hubert@intel.com>
Signed-off-by: Arun Ravindran <arun.ravindran@intel.com>
Signed-off-by: Jeevaka Badrappan <jeevaka.badrappan@intel.com>
Signed-off-by: Shuo Gao <shuo.gao@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 577