anv: Add support for the variablePointers feature

Not to be confused with variablePointersStorageBuffer which is the
subset of VK_KHR_variable_pointers required to enable the extension.
This means we now have "full" support for variable pointers.

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>

src/intel/vulkan/anv_device.c

@@ -728,7 +728,7 @@ void anv_GetPhysicalDeviceFeatures2KHR(
       case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR: {
          VkPhysicalDeviceVariablePointerFeaturesKHR *features = (void *)ext;
          features->variablePointersStorageBuffer = true;
-         features->variablePointers = false;
+         features->variablePointers = true;
          break;
       }