starpu/codelet: switch names to const char *

control/common.h

runtime/starpu/codelets/codelet_gemm.c

runtime/starpu/codelets/codelet_hgemm.c

runtime/starpu/codelets/codelet_zgemm.c

runtime/starpu/codelets/codelet_zgetrf_blocked.c

runtime/starpu/codelets/codelet_zgetrf_percol.c

runtime/starpu/codelets/codelet_zhemm.c

runtime/starpu/codelets/codelet_zherk.c

runtime/starpu/codelets/codelet_zlascal.c

runtime/starpu/codelets/codelet_zlaset.c

runtime/starpu/codelets/codelet_zlauum.c

runtime/starpu/codelets/codelet_zplghe.c

runtime/starpu/codelets/codelet_zplgsy.c

runtime/starpu/codelets/codelet_zplrnt.c

runtime/starpu/codelets/codelet_zpotrf.c

runtime/starpu/codelets/codelet_zsymm.c

runtime/starpu/codelets/codelet_zsyrk.c

runtime/starpu/codelets/codelet_ztradd.c

runtime/starpu/codelets/codelet_ztrmm.c

runtime/starpu/codelets/codelet_ztrsm.c