uboot-imx

MLK-21956-3 mx6qdlsabreauto: Enable i2c gpio mux to fix io expander issue

The i2c gpio mux is not enabled, this causes i2c3 not work and all
io expander devices on i2c3 not work.  So we will meet such as
"usb start" fail due to the VBUS is not power up.

The patch add the i2c mux and i2c gpio mux configs. And remove codes of
controlling i2c steering from board, since i2c gpio mux does same thing.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>