Move wcnss_service to vendor

Mark the WCNSS service as proprietary so that the binary ends up under
vendor.  Note that because this module doesn't include the init script
to start the service, each device that makes use of this module must
change the device specific init script used to start the service.

Bug: 64694113
Test: Ran downloader utility on Angelfish over WIFI
Change-Id: I71bcb1ba796b4dbe11d7aec7928f7e13d6485160