i2c: Remove i2c clients in reverse order

i2c clients should be removed in reverse order compared to the probe
(actually: bind) order. This matters when several clients depend on
each other.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>