linux-phytec-fsl

i2c: Export i2c_for_each_dev

Introduce i2c_for_each_dev(), an i2c device iterator with proper
locking for use by i2c-dev. This is needed so that we can get rid of
the attach_adapter and detach_adapter legacy callback functions.

Signed-off-by: Jean Delvare <khali@linux-fr.org>