Change in flashrom[master]: bitbang-spi.c: support clock polarity and phase

[Xiang Wang (Code Review)]

Attention is currently required from: Xiang Wang, Stefan Reinauer, Angel Pons.
Hello build bot (Jenkins), Stefan Reinauer, Edward O'Callaghan, Angel Pons,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/flashrom/+/49255

to look at the new patch set (#7).

Change subject: bitbang-spi.c: support clock polarity and phase
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bitbang-spi.c: support clock polarity and phase

SPI has four modes, which are determined by Clock polarity and Clock phase.
See https://en.wikipedia.org/wiki/Serial_Peripheral_Interface#Clock_polarity_and...
for details. The previous code only supports one mode and may not be able to
handle some special spi flash.

TEST=build and run flashrom with sysfsgpio on raspberrypi to read  W25Q128.V

Change-Id: I04c1dfe132d756119229b27c3cd611d1be1abc8d
Signed-off-by: Xiang Wang 
---
M bitbang_spi.c
1 file changed, 71 insertions(+), 19 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/55/49255/7