radv: Implement vk.check_status
Implement check_status function so the driver can check if the GPU has been reset by the application, and thus if it's still available.
AMDGPU_CTX_QUERY2 ioctl works by asking amdgpu if this context was the cause of a previous GPU reset.
On a side note, I would like to check just for contexts in use, but I couldn't find a way to do so.