Fixed warnings in the Vulkan project

Some classes were given the following attribute:
[[clang::lto_visibility_public]]

This produces a warning in Visual Studio.

This was meant to allow these base classes to be visible
to both libEGL and libGLESv2. Vulkan will be a single DLL,
so this won't be an issue, so I simply removed both
instances of this attribute in the Vulkan project.

Change-Id: I6d1b0bb0ab5351d6b788917c0b876e9355505404
Reviewed-on: https://swiftshader-review.googlesource.com/c/22428
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Device/Surface.hpp b/src/Device/Surface.hpp
index c24c57b..61e969d 100644
--- a/src/Device/Surface.hpp
+++ b/src/Device/Surface.hpp
@@ -315,7 +315,7 @@
 		LOCK_UPDATE   // Write access which doesn't dirty the buffer, because it's being updated with the sibling's data.
 	};
 
-	class [[clang::lto_visibility_public]] Surface
+	class Surface
 	{
 	private:
 		struct Buffer
diff --git a/src/WSI/FrameBuffer.hpp b/src/WSI/FrameBuffer.hpp
index 7ce1d17..761db18 100644
--- a/src/WSI/FrameBuffer.hpp
+++ b/src/WSI/FrameBuffer.hpp
@@ -37,7 +37,7 @@
 		int cursorHeight;
 	};
 
-	class [[clang::lto_visibility_public]] FrameBuffer
+	class FrameBuffer
 	{
 	public:
 		FrameBuffer(int width, int height, bool fullscreen, bool topLeftOrigin);