aco: set constant_data_offset correctly in the case of merged shaders
setup_nir() is done for all shaders before any of them are selected, so constant_data_offset could be incorrect for the first shader.
Fixes incorrect geometry in Mafia III demo.
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setup_nir() is done for all shaders before any of them are selected, so constant_data_offset could be incorrect for the first shader.
Fixes incorrect geometry in Mafia III demo.