nv50/ir: initialize persampleInvocation to false

Fixes: random KHR-GL45.sample_variables.mask.* fails
Fixes: 66ed9792ed ("nv50: Clear nv50_ir_prog_info of dead and codegen specific variables")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6001>

src/gallium/drivers/nouveau/codegen/nv50_ir.cpp

@@ -1182,6 +1182,7 @@ Program::Program(Type type, Target *arch)
 
    maxGPR = -1;
    fp64 = false;
+   persampleInvocation = false;
 
    main = new Function(this, "MAIN", ~0);
    calls.insert(&main->call);