Hammerhead camera: Fix unused variables

For build-system CFLAGS clean-up, fix unused variables.

This only cleans the parts of this project using -Werror.

Change-Id: I26ee6aa9c08c3f7ff5a28e4995bbcc4748910e94
Merge branch 'lp5.0' of https://github.com/AICP/device_lge_hammerhead into lollipop