spi: Make 'default_spi_write_aai' the default unless defined

A NULL func pointer is necessary and sufficient for the
condition `NULL func pointer => default_spi_write_aai' as to not
need this explicit specification of 'default'.

Therefore drop the explicit need to specify the 'default_spi_write_aai'
callback function pointer in the spi_master struct. This is a reasonable
default for every other driver in the tree with only a few exceptions.

This simplifies the code and driver development.

flashrom-stable: Updated `dirtyjtag_spi` which was added earlier.

Change-Id: I7f14aaea0edcf0c08cea0e9cd27d58152707fb2a
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/67479
Original-Reviewed-by: Peter Marheine <pmarheine@chromium.org>
Original-Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72369
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
18 files changed