anv: rename host only descriptor internal flag

We add an assert to verify that those are not bound.

v2: Drop != 0 (Tapani)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15241>

src/intel/vulkan/anv_private.h

@@ -2021,7 +2021,7 @@ struct anv_descriptor_pool {
 
    struct list_head desc_sets;
 
-   bool allocate_surface_states;
+   bool host_only;
 
    char data[0];
 };