remove additional version "1.0" from SecondaryViewportRelativeNV (KhronosGroup#379)

SecondaryViewportRelativeNV already has a version field

Author: rAzoR8

include/spirv/unified1/spirv.core.grammar.json

@@ -13009,8 +13009,7 @@
           "version" : "None",
           "parameters" : [
             { "kind" : "LiteralInteger", "name" : "'Offset'" }
-          ],
-          "version": "1.0"
+          ]
         },
         {
           "enumerant" : "PerPrimitiveNV",