Merge branch 'i2c-mux/for-next' of https://github.com/peda-r/i2c-mux into i2c/for-5.3

I realize that there are changes in drivers/i2c/busses/i2c-i801.c that strictly
speaking don't belong here, but I hope you don't mind. These changes are all
about the interaction with the i2c-mux-gpio code, and I did a test-merge a few
days ago w/o conflicts.

Anyway, the GPIO-work from Linus Walleij (with help from Serge Semin) in the
i2c-mux-gpio and i2c-arb-gpio-challenge drivers is the main feature.

diff --cc drivers/i2c/busses/i2c-i801.c
Simple merge