nv50/ir: add missing string for SV_WORK_DIM

Fixes: 2aa1197 ("nouveau: Add support for SV_WORK_DIM")
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

src/gallium/drivers/nouveau/codegen/nv50_ir_print.cpp

@@ -312,6 +312,7 @@ static const char *SemanticStr[SV_LAST + 1] =
    "BASEVERTEX",
    "BASEINSTANCE",
    "DRAWID",
+   "WORK_DIM",
    "?",
    "(INVALID)"
 };