tu: Prevent reading of stale VFD_MODE_CNTL value
Affects these tests with reg stomper enabled:
dEQP-VK.pipeline.monolithic.multisample.sample_locations_ext.verify_location.samples_*
Affects these tests with reg stomper enabled:
dEQP-VK.pipeline.monolithic.multisample.sample_locations_ext.verify_location.samples_*