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

[Nico Huber (Code Review)]

Attention is currently required from: Edward O'Callaghan, Angel Pons, Anastasia Klimchuk.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/56825 )

Change subject: opaque_master: Use new API to register shutdown function
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Patch Set 1: Code-Review+1

(2 comments)

File linux_mtd.c:

https://review.coreboot.org/c/flashrom/+/56825/comment/445c183d_d4b32a7b 
PS1, Line 421: 	if (register_shutdown(linux_mtd_shutdown, (void *)data)) {
Looks like this is also fixing leakage of a file descriptor.

File nicintel_eeprom.c:

https://review.coreboot.org/c/flashrom/+/56825/comment/254d6472_4efc3b3c 
PS1, Line 497: 
             : 		return register_opaque_master(&opaque_master_nicintel_ee_82580, eecp);
> The piece of data, eecp, is only used in shutdown function, and not used as opaque_master data (prev […]

Sounds correct.