hwcomposer: Add HWC_DISPLAY_SECURE as a dpy attribute

- HWC_DISPLAY_SECURE attribute will be used by SurfaceFlinger
  to determine if the display is secure.
- This property will be set to true if the display is secure based on HDCP

Change-Id: I9c01239521e81ae3d863e9bfbba0de72264dc14c
audio: Add audio parameter key for device connect

Add audio parameter key for device connect.

Bug: 17785277
Change-Id: Icd81702634e0bd83645d89c2d65e2b303fc11f8c