mesa: add SEVERITY_NOTIFICATION to default state
mesa: add SEVERITY_NOTIFICATION to default state

As per the spec quote:

    "All messages are initially enabled unless their assigned severity
    is DEBUG_SEVERITY_LOW"

We already had MEDIUM and HIGH set, let's toggle NOTIFICATION as well.

Signed-off-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>
Reviewed-by: Timothy Arceri <5dd83789ef3714029244367ba1ca09f1d7627408@collabora.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler