Constify option parameter for better compiler analysis

include/runtime.h

include/runtime_z.h

runtime/parsec/codelets/codelet_dataflush.c

runtime/parsec/codelets/codelet_zasum.c

runtime/parsec/codelets/codelet_zaxpy.c

runtime/parsec/codelets/codelet_zbuild.c

runtime/parsec/codelets/codelet_zgeadd.c

runtime/parsec/codelets/codelet_zgelqt.c

runtime/parsec/codelets/codelet_zgemm.c

runtime/parsec/codelets/codelet_zgeqrt.c

runtime/parsec/codelets/codelet_zgessm.c

runtime/parsec/codelets/codelet_zgessq.c

runtime/parsec/codelets/codelet_zgetrf.c

runtime/parsec/codelets/codelet_zgetrf_incpiv.c

runtime/parsec/codelets/codelet_zgetrf_nopiv.c

runtime/parsec/codelets/codelet_zhemm.c

runtime/parsec/codelets/codelet_zher2k.c

runtime/parsec/codelets/codelet_zherk.c

runtime/parsec/codelets/codelet_zhessq.c

runtime/parsec/codelets/codelet_zlacpy.c