treewide: remove stale mentions of CONFIG_OF in comments ...

barebox doesn't define a CONFIG_OF kconfig option, but CONFIG_OFTREE
for the device tree handling and CONFIG_OFDEVICE for probing devices
out of the device tree.

Replace comment mentions of CONFIG_OF with mentions of either as
appropriate.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c: import multiplexed I2C bus core support from linux kernel ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>