Identity equality for arguments of types Int and Int is deprecated

Just fyi, this is my first question on StackOverflow and I'm really new in Kotlin.

While working on a project that's fully Kotlin (ver 1.1.3-2), I see a warning on the following code (with the comments for you curious lads):

    // Code below is to handle presses of Volume up or Volume down.
    // Without this, after pressing volume buttons, the navigation bar will
    // show up and won't hide
    val decorView = window.decorView
    decorView
        .setOnSystemUiVisibilityChangeListener { visibility ->
            if (visibility and View.SYSTEM_UI_FLAG_FULLSCREEN === 0) {
                 decorView.systemUiVisibility = flags
            }
        }

The warning is for visibility and View.SYSTEM_UI_FLAG_FULLSCREEN === 0, and it says Identity equality for arguments of types Int and Int is deprecated.

How should I change the code and why was it deprecated in the first place (for knowledge's sake)?