Mark gpu_usage as const

Bug: 131181334
Test: make
Change-Id: I317e265594471e0a0eaf81a6520d497a558a2a32
Merged-In: I2feefa3e180a6f19be532db3e9f11b593bcdf47f
Signed-off-by: Roman Kiryanov <rkir@google.com>

system/vulkan_enc/AndroidHardwareBuffer.cpp

@@ -67,7 +67,7 @@ VkResult getAndroidHardwareBufferPropertiesANDROID(
         AHardwareBuffer_Desc desc;
         AHardwareBuffer_describe(buffer, &desc);
 
-       uint64_t gpu_usage =
+       const uint64_t gpu_usage =
           AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE |
           AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT |
           AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER;