i2c: Race fix for i2c-mpc.c

The problem was that the clock speed and driver data is
initialized after the i2c adapter was added. This caused
the i2c bus to start working at a wrong speed. (Mostly
noticable on the second bus on mpc5200)

With this patch we've tried to keep the i2c adapter
working perfectly all the time it is included in the system.
Initialize before added, Remove garbage after deleleted.

Submitted-by: Asier Llano Palacios
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>