Change in flashrom[master]: bitbang: Extend register_spi_bitbang_master() API with spi data

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Nico Huber, Angel Pons, Anastasia Klimchuk.
Edward O'Callaghan has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/54990 )

Change subject: bitbang: Extend register_spi_bitbang_master() API with spi data
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Patch Set 1: Code-Review+1

(1 comment)

File bitbang_spi.c:

https://review.coreboot.org/c/flashrom/+/54990/comment/5cff25e5_2a184792 
PS1, Line 164: 	mst.data = data;
             : 	register_spi_master(&mst, NULL);
I feel like the removal of `mst.data = data;` and instead passing data directly into register_spi_master() is itself a patch. small granted but none the less technically not within the scope of this patch.