Revert "Merge branch 'mctp-i2c-driver'"

Revert "Merge branch 'mctp-i2c-driver'"

This reverts commit cea9d982e9e40edd9a38fa81185ce28238c2c18b, reversing
changes made to 79e7716c7d34046c3459faa9aebc7d09946e9fe0.

Wolfram Sang says:

Please revert. Besides the driver in net, it modifies the I2C core
code. This has not been acked by the I2C maintainer (in this case me).
So, please don't pull this in via the net tree. The question raised here
(extending SMBus calls to 255 byte) is complicated because we need ABI
backwards compatibility.

Link: https://lore.kernel.org/all/YZJ9H4eM%2FM7OXVN0@shikoro/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>