[S] Change in flashrom[master]: spi: Make 'default_spi_send_command' the default unless defined

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Thomas Heijligen.

Edward O'Callaghan has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/67480 )

Change subject: spi: Make 'default_spi_send_command' the default unless defined
......................................................................

Patch Set 3:

(2 comments)

Commit Message:

https://review.coreboot.org/c/flashrom/+/67480/comment/79dad23a_48468c9f 
PS1, Line 9: Drop the explicit need to specify the default
> Please mention the struct where you perform the changes on

Done

Patchset:

PS1:
> I think setting optionally one of `.command` or `. […]

I totally agree with the second sentence however for the first, is this not just a stepping stone towards that eventual path? A driver need only now need to define either a `.command` or `.multicommand` variant explicitly and inherit the `NULL` case intrinsically. Therefore to realise the suggested concept is than a matter of unifying the explicit case.