vulkan: fix compile error with latest AHB changes

Otherwise, the following error is observed:

frameworks/native/vulkan/include/vulkan/vk_android_native_buffer.h:128:5:
   error: must use 'struct' tag to refer to type 'AHardwareBuffer'

BUG=313466265
TEST=presubmit

Change-Id: I1d32208a26161a64cba057a9fb4a47ce28b83d5b
diff --git a/vulkan/include/vulkan/vk_android_native_buffer.h b/vulkan/include/vulkan/vk_android_native_buffer.h
index 3e3f962..159b2d5 100644
--- a/vulkan/include/vulkan/vk_android_native_buffer.h
+++ b/vulkan/include/vulkan/vk_android_native_buffer.h
@@ -125,7 +125,7 @@
     int                               usage; /* DEPRECATED in SPEC_VERSION 6 */
     VkNativeBufferUsage2ANDROID       usage2; /* DEPRECATED in SPEC_VERSION 9 */
     uint64_t                          usage3; /* ADDED in SPEC_VERSION 9 */
-    AHardwareBuffer*                  ahb; /* ADDED in SPEC_VERSION 11 */
+    struct AHardwareBuffer*           ahb; /* ADDED in SPEC_VERSION 11 */
 } VkNativeBufferANDROID;
 
 /*