configure.ac: perform RISC-V vector crypto intrinsics bug checks without LTO
* configure.ac (gcry_cv_riscv_vsha2cl_intrinsics_work) (gcry_cv_riscv_vaes_vs_intrinsics_work): Run check with '-fno-lto' compiler flag.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>