fbdev: msm: update event callback function to perform ESD check

Fix the string comparision logic in fb_event_callback so
that the ESD periodic check functionality gets enabled.

Change-Id: Ic6b40f1df5a7b9ce8b588352bcec6ba265f19c30
Signed-off-by: Althaf Neelanchirayil <aneelanc@codeaurora.org>
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>