Fix format used for Skylake UNC_ARB_TRK_OCCUPANCY.DATA_READ:c1

uncore_arb on Skylake has no thresh format, it should use cmask. This
confusion creeps in because on SkylakeX uncore_cha is used instead of
uncore_arb, uncore_cha having a thresh format.

scripts/create_perf_json.py

@@ -976,7 +976,7 @@ def fixup(form: str) -> str:
                         'RKL': td_event_fixups,
                         'SKL': [
                             ('UNC_ARB_TRK_OCCUPANCY.DATA_READ:c1',
-                             'UNC_ARB_TRK_OCCUPANCY.DATA_READ@thresh\=1@'),
+                             'UNC_ARB_TRK_OCCUPANCY.DATA_READ@cmask\=1@'),
                         ],
                         'SKX': [
                             ('UNC_M_CLOCKTICKS:one_unit', 'imc_0@event\=0x0@'),