i2c-mpc: work around missing-9th-clock-pulse bug

Work around a problem reported on:
http://ozlabs.org/pipermail/linuxppc-embedded/2005-July/019038.html
Without this patch I2C on mpc5200 becomes unusable after a while.
Tested on mpc5200 boards by Matthias Fechner and me.

Signed-off-by: Domen Puncer <domen.puncer@telargo.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>