Allow wificond to run as wifi:wifi

Expose the firmware path from libwifi_hal.
We need to access this at wificond startup to chown the firmware
reload path to wifi:wifi.

Remove some superfluous chown calls.  The callsites should only
be used from wificond.

Bug: 29870863
Test: wificond unit and integration tests pass

Change-Id: If2fa38be252999a01f6d967ca8601d1789318103
6 files changed
tree: a976c7d64b1851f861561227c9602bf24438840e
  1. libwifi_hal/
  2. libwifi_system/
  3. service/
  4. tests/