lib: sbi: Add support for smcsrind and smcdeleg

Smcsrind allows generic indirect CSR access mechanism while
Smcdeleg allows delegating hpmcounters in Supervisor mode.

Enable both extensions and set the appropriate bits in mstateen
and menvcfg.

Co-developed-by: Kaiwen Xue <kaiwenxue1@gmail.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>