lib: sbi_misaligned_ldst: Remove mcause, scratch and hartid parameters

We remove mcause, scratch and hartid parameters from various functions
for misaligned load/store handling 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>