[S] Change in flashrom[master]: programmer.h: Guard against sending spi commands on non-spi mst

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Felix Singer, Edward O'Callaghan.

Hello Felix Singer, build bot (Jenkins), Angel Pons,

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

https://review.coreboot.org/c/flashrom/+/71269

to look at the new patch set (#2).

Change subject: programmer.h: Guard against sending spi commands on non-spi mst
......................................................................

programmer.h: Guard against sending spi commands on non-spi mst

Validate (flash->chip->bustype == BUS_SPI) as ich copies the
chip flags in the opaque master and tries incorrectly
to issue 4BA commands which results in failure.

The issue was detected only in the case of chips >16MB, in
this case 'W25Q256FV' that has the feature bits:
```
 .feature_bits   = FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_ENTER_WREN |
                   FEATURE_4BA_EAR_C5C8 | FEATURE_4BA_READ | FEATURE_4BA_FAST_READ |
                   FEATURE_WRSR2,
```
The regression was noticed from,
commit 0741727925b841c2479b993204ce58c5eb75185a ichspi.c: Read chip ID and use it to populate `flash->chip`

TEST=In the case of 'W25Q256FV' on TigerLake.

Change-Id: I7cce4f9c032d33c01bf616e27a50b9727a40fe1b
Signed-off-by: Edward O'Callaghan 
---
M flashrom.c
M include/programmer.h
2 files changed, 33 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/69/71269/2