par_master: Use new API to register shutdown function

This allows par masters to register shutdown function in par_master
struct, which means there is no need to call register_shutdown in init
function, since this call is now a part of register_par_master.

As a consequence of using new API, this patch also fixes propagation
of register_par_master() return values.

Tested: builds and ninja test

Change-Id: Ief7be907f53878b4b6567b52889735e5fff64ead
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/57156
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72233
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed