time: Add rq_stats snapshot

Add snapshot of runqueue stats module as of commit <e56fe938419e>
(Merge "uapi: Introduce V4L2_FLAG_CVPMETADATA_SKIP flag").

Added #ifdefery to allow rq_stats to actually be optional.

Change-Id: I3352a472c5b0ad61cc04317a1d6f26549bfcdc04
Signed-off-by: Elliot Berman <eberman@codeaurora.org>