lavapipe: store number of immutable samplers to pipeline layout

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15462>

src/gallium/frontends/lavapipe/lvp_descriptor_set.c

@@ -70,6 +70,7 @@ VKAPI_ATTR VkResult VKAPI_CALL lvp_CreateDescriptorSetLayout(
    vk_object_base_init(&device->vk, &set_layout->base,
                        VK_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT);
    set_layout->ref_cnt = 1;
+   set_layout->immutable_sampler_count = immutable_sampler_count;
    /* We just allocate all the samplers at the end of the struct */
    struct lvp_sampler **samplers =
       (struct lvp_sampler **)&set_layout->binding[num_bindings];

src/gallium/frontends/lavapipe/lvp_private.h

@@ -346,6 +346,8 @@ struct lvp_descriptor_set_layout {
    /* Descriptor set layouts can be destroyed at almost any time */
    uint32_t ref_cnt;
 
+   uint32_t immutable_sampler_count;
+
    /* Number of bindings in this descriptor set */
    uint16_t binding_count;