zink: fix 64bit float shader ops

this was being set from back before zink actually supported 64bit natively and only 32bit was functional, but it breaks 64bit support

cc: mesa-stable

fixes (lavapipe): KHR-GL46.gpu_shader_fp64.builtin.mod_dvec2 KHR-GL46.gpu_shader_fp64.builtin.mod_dvec3 KHR-GL46.gpu_shader_fp64.builtin.mod_dvec4