vulkan: Set up VkCmdBuffer dispatching

Change-Id: Ifb3cea05dab8828c2c00b8ed60c5ad991cdcbea7
(cherry picked from commit 10bf73e13b6904afa606fdcdc05bcc510c605180)
diff --git a/vulkan/libvulkan/loader.h b/vulkan/libvulkan/loader.h
index 1f6a1d4..fad92a7 100644
--- a/vulkan/libvulkan/loader.h
+++ b/vulkan/libvulkan/loader.h
@@ -187,6 +187,9 @@
                         uint32_t family,
                         uint32_t index,
                         VkQueue* out_queue);
+VkResult CreateCommandBuffer(VkDevice device,
+                             const VkCmdBufferCreateInfo* create_info,
+                             VkCmdBuffer* out_cmdbuf);
 VkResult DestroyDevice(VkDevice drv_device);
 
 // -----------------------------------------------------------------------------