uboot-phytec

pinctrl: imx: Fix mask when SHARE_MUX_CONF_REG is set

when using SHARE_MUX_CONF_REG, wrong mask is used for
writing config value, which causes mux value is cleared.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>