v3dv: don't reset loader data on command buffers

We were clearing memory to 0 on create and reset, including the
loader data, which is not correct on reset since it would cleat
the loader dispatch table for the command buffer. We should only
clear driver data.

Also, don't use vk_zalloc for the command buffer allocation, since
we are already clearing on reset and we always reset when we begin
recording.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
1 file changed