radv: reset pending_reset_query when flushing caches

radv: reset pending_reset_query when flushing caches

If the driver used a compute shader for resetting a query pool,
it should be completed when caches are flushed.

This might reduce the number of stalls if operations are done
between vkCmdResetQueryPool() and vkCmdBeginQuery()
(or vkCmdWriteTimestamp()).

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Alex Smith <asmith@feralinteractive.com>