uboot-phytec

i2c: designware_i2c: Don't allow changing IC_CLK

If a different input clock is required then the correct way to do this is
with a clock driver. Don't allow boards to override IC_CLK.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>