radv: fix queries with WAIT_BIT returning VK_NOT_READY

radv: fix queries with WAIT_BIT returning VK_NOT_READY

When vkGetQueryPoolResults() is called with VK_QUERY_RESULT_WAIT_BIT
set, the driver is supposed to wait for the query to become available
before returning.

Currently, radv returns once the query is indeed ready, but it returns
VK_NOT_READY. It also fails to populate the results.

The problem is a missing volatile in the secondary check for query
availability. This patch removes the secondary check altogether since it
is redundant with the preceding loop.

This bug was found with an unreleased version of SteamVR.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>