[PATCH] I2C: Separate non-i2c hwmon drivers from i2c-core (1/9)

Temporarily export a few structures and functions from i2c-core, because we
will soon need them in i2c-isa.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>