display: Remove poll.c

display: Remove poll.c

poll.c file has legacy functions pm_change_internal/pm_lock_internal/pm_unlock_internal()
These functions are usually called from external requests like key-event, dbus method, etc.
pm_lock_internal/pm_unlock_internal() gets specific display state lock/unlock.
pm_change_internal() requests state transition according to specific condition.
This file has to be erased, and then inner functions are relocated.

These are new functions to be added.
display-lock
- int display_lock_request_lock_with_option(pid_t pid, int s_bits, int flag, int timeout);
- int display_lock_request_unlock_with_option(pid_t pid, int s_bits, int flag);
    -> These replace pm_lock_internal/pm_unlock_intenral().

display-state-transition
- int display_state_transition_request_state_transition_with_option(pid_t pid, int s_bits);
    -> This replaces pm_change_internal().

display-util
- int display_util_get_display_state(int s_bits);
    -> This extracts display state from s_bits.

Change-Id: Ied90f5a7f132f3bfcba1ecf1eef8faa02c728e31
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>