git: openjdk/jfx-sandbox: metal: Fix warning

[Ambarish Rapte]

Changeset: a22afcf5
Author:    Ambarish Rapte <arapte at openjdk.org>
Date:      2023-02-09 14:54:34 +0000
URL:       https://git.openjdk.org/jfx-sandbox/commit/a22afcf5f198059fe7b922f198db0b64ed81b2cb

Fix warning

! modules/javafx.graphics/src/main/java/com/sun/prism/mtl/MTLContext.java
! modules/javafx.graphics/src/main/native-prism-mtl/MetalContext.m