Convert i2c-isa from a dumb i2c_adapter into a pseudo i2c-core for ISA
hardware monitoring drivers. The isa i2c_adapter is no more registered
with i2c-core, drivers have to explicitely connect to it using the new
i2c_isa_{add,del}_driver interface.

At this point, all ISA chip drivers are useless, because they still
register with i2c-core in the hope i2c-isa is registered there as well,
but it isn't anymore.

The fake bus will be named i2c-9191 in sysfs. This is the number it
already had internally in various places, so it's not exactly new,
except that now the number is seen in userspace as well. This shouldn't
be a problem until someone really has 9192 I2C busses in a given system
;)

The fake bus will no more show in "i2cdetect -l", as it won't be seen by
i2c-dev anymore (not being registered with i2c-core), which is a good
thing, as i2cdetect/i2cdump/i2cset cannot operate on this fake bus
anyway.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!