[NFC][libclc][CMake] Remove redundant dependency on prepare-${obj_suffix}#20298

againull merged 1 commit intointel:syclintel/llvm:syclfrom

wenju-he:libclc-remove-redundant-add_dependencies-preparewenju-he/llvm:libclc-remove-redundant-add_dependencies-prepareCopy head branch name to clipboard