i2c: Workaround bad clock-frequency property from HostBoot
i2c: Workaround bad clock-frequency property from HostBoot

The cell clock is 50Mhz on P8, not 600Mhz ! Remove this when HB has
been fixed.

Signed-off-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>
Signed-off-by: Jeremy Kerr <68a658b44bbaefab3ef5cd231967195fc0ff9d69@ozlabs.org>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

jk-ozlabs/skiboot,open-power/skiboot,legoater/skiboot,cyrilbur-ibm/skiboot,apopple/skiboot,ddstreet/skiboot,cyrilbur-ibm/skiboot,csmart/skiboot,stewart-ibm/skiboot,apopple/skiboot,mikey/skiboot,cyrilbur-ibm/skiboot,stewart-ibm/skiboot,jk-ozlabs/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,csmart/skiboot,shenki/skiboot,jk-ozlabs/skiboot,ddstreet/skiboot,qemu/skiboot,mikey/skiboot,shenki/skiboot,legoater/skiboot,open-power/skiboot,stewart-ibm/skiboot,ddstreet/skiboot,open-power/skiboot,shenki/skiboot,apopple/skiboot,csmart/skiboot,qemu/skiboot,mikey/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,qemu/skiboot