vulkan/runtime: Add a level field to vk_command_buffer

Looks like 3 implementations already have that field in their private
command_buffer struct, and having it at the vk_command_buffer opens the
door for generic (but suboptimal) secondary command buffer support.

Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14917>

src/vulkan/runtime/vk_command_buffer.h

@@ -34,6 +34,9 @@ extern "C" {
 struct vk_command_buffer {
    struct vk_object_base base;
 
+   /** VkCommandBufferAllocateInfo::level */
+   VkCommandBufferLevel level;
+
    /**
     * VK_EXT_debug_utils
     *
@@ -80,7 +83,8 @@ VK_DEFINE_HANDLE_CASTS(vk_command_buffer, base, VkCommandBuffer,
 
 VkResult MUST_CHECK
 vk_command_buffer_init(struct vk_command_buffer *command_buffer,
-                       struct vk_device *device);
+                       struct vk_device *device,
+                       VkCommandBufferLevel level);
 
 void
 vk_command_buffer_reset(struct vk_command_buffer *command_buffer);