imx-common: consider mux_ctrl_ofs when setting mux_mode

imx-common: consider mux_ctrl_ofs when setting mux_mode

Some i.MXes use __NA_ or 0 to avoid setting mux_mode, but the following patch
only take i.MX6/7 into consideration.

"c3c8a5748897b24f18618047804317167a531dd3 imx-common: fix iomux settings"

Use is_soc_type(MXC_CPU_MX7) to avoid breaking other i.MXes when
setting mux_mode.

In this patch, switch to use "asm/imx-common/sys_proto.h" to avoid
build break for "is_soc_type" for vf610 and mx25.

Signed-off-by: Peng Fan <[email protected]>
Cc: Bhuvanchandra DV <[email protected]>
Cc: Stefano Babic <[email protected]>
Cc: Fabio Estevam <[email protected]>
Acked-by: Stefano Babic <[email protected]>
Reviewed-by: Benoît Thébaudeau <[email protected]>