lib: sbi: Use AIA CSRs for local interrupts when available

We should use AIA CSRs to process local interrupts whenever AIA
is available.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>