Vulkan: remove some redundant codes

Bug: 134185757
Test: build
Change-Id: I843f361e31d098bc1f0ab2de67aac1e1161aa351
diff --git a/vulkan/libvulkan/driver.cpp b/vulkan/libvulkan/driver.cpp
index c3c19ec..4aa7d55 100644
--- a/vulkan/libvulkan/driver.cpp
+++ b/vulkan/libvulkan/driver.cpp
@@ -1208,7 +1208,6 @@
     }
 
     data->driver_device = dev;
-    data->driver_version = properties.driverVersion;
 
     *pDevice = dev;
 
diff --git a/vulkan/libvulkan/driver.h b/vulkan/libvulkan/driver.h
index 61e1818..7edadea 100644
--- a/vulkan/libvulkan/driver.h
+++ b/vulkan/libvulkan/driver.h
@@ -98,7 +98,6 @@
 
     VkDevice driver_device;
     DeviceDriverTable driver;
-    uint32_t driver_version;
 };
 
 bool Debuggable();