If we were to ever encounter a sample_flags mismatch we need to ensure
we destroy the stream when we bail.

Fixes: d7965152 ("drm/i915: Enable i915 perf stream for Haswell OA unit")
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Robert Bragg <robert@sixbynine.org>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327203459.18398-1-matthew.auld@intel.com
(cherry picked from commit 22f880ca)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>