drm/i915/perf: replace BUG_ON() with WARN_ON()

Avoid BUG_ON(). Replace with WARN_ON() and early return.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220830093411.1511040-4-jani.nikula@intel.com

drivers/gpu/drm/i915/i915_perf.c

@@ -1376,7 +1376,8 @@ static void i915_oa_stream_destroy(struct i915_perf_stream *stream)
 {
 	struct i915_perf *perf = stream->perf;
 
-	BUG_ON(stream != perf->exclusive_stream);
+	if (WARN_ON(stream != perf->exclusive_stream))
+		return;
 
 	/*
 	 * Unset exclusive_stream first, it will be checked while disabling