riscv: hwprobe: export Zhintntl ISA extension

Export Zihintntl extension[1] through hwprobe.

Link: https://drive.google.com/file/d/13_wsN8YmRfH8YWysFyTX-DjTkCnBd9hj/view

 [1]
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20231114141256.126749-14-cleger@rivosinc.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>