the incoming-call screen is displayed when phone is locked while receiving incoming call.
issue:the unlock screen is display when phone is locked while receiving incoming call,the incoming call screen should be displayed.
howto: add WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED to InCallScreen.

Change-Id: Ia377b8c2b82271f252b88fc1348204f753da30d7
Signed-off-by: annieyu <annieyu@huaqin.com>