powerpc/83xx: Move mcu_mpc8349emitx driver out of drivers/i2c/chips/

This patch is used to help Jean Delvare to get rid of drivers/i2c/chips/
directory. The new location suggested by Kumar Gala: as the driver is
83xx specific it's placed into arch/powerpc/platforms/83xx/.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>