mpc83xx: correctly set encryption and I2C bus 0 clock

This patch makes sure the correct mask is applied when setting
the encryption and I2C bus 0 clock in SCCR.
Failing to do so may lead to ENCCM being 0 in which case I2C bus 0
won't function.

Signed-off-by: Norbert van Bolhuis <nvbolhuis@aimvalley.nl>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>