Change in flashrom[master]: spi_master: Use new API to register shutdown function

[Anastasia Klimchuk (Code Review)]

Attention is currently required from: Nico Huber, Thomas Heijligen, Edward O'Callaghan, Angel Pons.
Anastasia Klimchuk has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/56103 )

Change subject: spi_master: Use new API to register shutdown function
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Patch Set 1:

(1 comment)

Patchset:

PS1: 
I have a message to reviewers, thank you!
1) I don't know how to build ni845x_spi
2) raiden_debug_spi is left for now, it has different data used in register_spi_master vs register_shutdown
3) Dummy and serprog are left for now, they are 2 in 1: spi and par
4) Internal and ichspi do not call register_shutdown function, so they are not here.

I plan to test this on devices tomorrow and will update.