Improve Windows vulkan draw performance by reducing the size of a struct.

src/modules/graphics/vertex.h

@@ -298,9 +298,12 @@ struct BufferBindings
 
 struct VertexAttributeInfo
 {
-	uint8 bufferIndex;
-	DataFormat format : 8;
 	uint16 offsetFromVertex;
+	uint8 packedFormat;
+	uint8 bufferIndex;
+
+	void setFormat(DataFormat format) { packedFormat = (uint8)format; }
+	DataFormat getFormat() const { return (DataFormat)packedFormat; }
 };
 
 struct VertexBufferLayout
@@ -335,7 +338,7 @@ struct VertexAttributes
 		enableBits |= (1u << index);
 
 		attribs[index].bufferIndex = bufferindex;
-		attribs[index].format = format;
+		attribs[index].setFormat(format);
 		attribs[index].offsetFromVertex = offsetfromvertex;
 	}