Add missing includes to SemaphoreService.h

These are needed for the VulkanDeviceInfo and VulkanFunctions structs.

Change-Id: I1d18e59cd923e5fd702ac65d505793519b3a42b7
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/62920
Commit-Queue: James Price <jrprice@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>

src/dawn_native/vulkan/external_semaphore/SemaphoreService.h

@@ -18,6 +18,8 @@
 #include "common/vulkan_platform.h"
 #include "dawn_native/Error.h"
 #include "dawn_native/vulkan/ExternalHandle.h"
+#include "dawn_native/vulkan/VulkanFunctions.h"
+#include "dawn_native/vulkan/VulkanInfo.h"
 
 namespace dawn_native { namespace vulkan {
     class Device;