We should check and access N-extension CSRs in sbi_hart_switch_mode()
when next_mode is u-mode because N-extension is optional.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>