vkr: log for more CS errors
We've got bug reports with
vkr: vkExecuteCommandStreamsMESA resulted in CS error
and nothing else.
As far as I can tell, the decoder, the encoder, and vn_dispatch_command all log on CS errors. The problem should be in vkr_dispatch_vkExecuteCommandStreamsMESA. Make vkr_dispatch_vkExecuteCommandStreamsMESA chatty as well.