libvulkan: Fix for -Wcast-calling-convention

It should be harmless, as NoOp does not use any argument and should never
be reached.

Bug: 30290462
Change-Id: I0592c3ce10c510713525b5aa0bd38a2f9adc5898
diff --git a/vulkan/libvulkan/stubhal.cpp b/vulkan/libvulkan/stubhal.cpp
index a74d370..869317b 100644
--- a/vulkan/libvulkan/stubhal.cpp
+++ b/vulkan/libvulkan/stubhal.cpp
@@ -43,7 +43,7 @@
 static std::bitset<kMaxInstances> g_instance_used(false);
 static std::array<hwvulkan_dispatch_t, kMaxInstances> g_instances;
 
-[[noreturn]] void NoOp() {
+[[noreturn]] VKAPI_ATTR void NoOp() {
     LOG_ALWAYS_FATAL("invalid stub function called");
 }