does drive_get_next(IF_NONE) make sense?

[Peter Maydell]

Does it make sense for a device/board to do drive_get_next(IF_NONE) ?

At the moment we have exactly one user of this, which is
hw/misc/sifive_u_otp.c. This is a model of a one-time-programmable
fuse, and the drive is providing the backing store for the fuse
contents. Borrowing an IF_NONE for this seems a bit odd, but
it's not clear any of the other IF_ types is better.

We also just (this release cycle) added models of the Xilinx
efuse OTP fuses. Those have been implemented to use IF_PFLASH.
(This is a somewhat unfortunate inconsistency I guess.)

We also have a patchseries currently in the code review stage
which uses IF_NONE:
20211101232346.1070813-1-wuhaotsh@google.com/20211101232346.1070813-6-wuhaotsh@google.com/">https://patchew.org/QEMU/20211101232346.1070813-1-wuhaotsh@google.com/20211101232346.1070813-6-wuhaotsh@google.com/
Here we are trying to provide a drive as backing store for some
EEPROMs that hang off the i2c buses on some npcm7xx boards.

Are these uses of IF_NONE OK, or should we be doing something
else (using IF_PFLASH, defining a new IF_*, ???)

thanks
-- PMM