display: state-transition: Relocate default_trans()

display: state-transition: Relocate default_trans()

default_trans() was used for display state transition.
1. It gets next display state and checks if the state transition is possible or not.
2. And then, it updates old/current display state.
3. Finally, it goes to next state transition or default_action if possible.

These functions are added below display-state-transition.
- int display_state_transition_do_state_transition(enum state_t state, int evt_type);
    -> This replaces default_trans()
- bool display_state_transition_is_display_state_support_transition(enum state_t state);
    -> This function checks if state is support to do state transition related job.
       For example,
         1. checking state transition condition
         2. do state transition
         3. do state action
    To check these, this function is added.

Change-Id: Icc58965838e30fde2871c1c69596ffbed43e60f2
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>