lib: sbi_emulate_csr: Remove scratch and hartid parameter

We remove scratch and hartid parameter from various functions
for CSR emulation because we can always get current HART id
and current scratch pointer using just one CSR access.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>