staging/android: prepare sw_sync files for de-staging

remove file paths in the comments and add short description about each
file.

v2: remove file paths instead of just change them.

v3: improve header description as sugggested by Eric

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>