Change in flashrom[master]: spi25_statusreg,flashchips: add SR2 read/write support

[Nico Huber (Code Review)]

Attention is currently required from: Edward O'Callaghan, Nikolai Artemiev, Sergii Dmytruk.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/58570 )

Change subject: spi25_statusreg,flashchips: add SR2 read/write support
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Patch Set 18:

(2 comments)

File flashchips.c:

https://review.coreboot.org/c/flashrom/+/58570/comment/549e9b15_1d5ea58e 
PS18, Line 6711: FEATURE_WRSR_EXT
The datasheet suggests this won't work, AFAICT, and I guess this path
is not tested because the code checks `FEATURE_WRSR2` first? You could
test it by removing the latter.

https://review.coreboot.org/c/flashrom/+/58570/comment/5dbbe1d7_f85a54f2 
PS18, Line 6872: 		.feature_bits   = FEATURE_WRSR_WREN | FEATURE_OTP,
Spurious change?