radv: clear push_constant_stages when resetting a command buffer

radv: clear push_constant_stages when resetting a command buffer

Per the spec:

   "Resetting a command buffer is an operation that discards any
   previously recorded commands and puts a command buffer in the
   initial state."

As far I'm concerned, that flag can be changed by calling
VkCmdPushConstants() (or any other functions which update it),
so it should be cleared as well.

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