staging/android: remove sw_sync.[ch] files

We can glue the sw_sync file operations directly on the sync framework
without the need to pass through sw_sync wrappers.

It only builds sw_sync debugfs file support if CONFIG_SW_SYNC is enabled.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>