i.mx6dl only support one single IPU, up to 2 displays.
change fb_data sequence for i.mx6dl support.

The following command options can be used for the display
tests on i.mx6dl sabresd boards.
- HDMI:
 video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24
- LVDS0:
 None or ldb=sin0, ldb=sep0
- LVDS1:
 ldb=sep1
- SEIKO-WVGA:
 video=mxcfb0:dev=lcd,SEIKO-WVGA,if=RGB24
- CLAA-WVGA:
 video=mxcfb0:dev=lcd,CLAA-WVGA,if=RGB565
- HDMI + LVDS0:
 video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24 ldb=sin0
 (or ldb=sep0)
 echo 0 > /sys/class/graphics/fb2/blank
- HDMI + LVDS1:
 video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24 ldb=sep1 (sin1
 is not supported)
 echo 0 > /sys/class/graphics/fb2/blank
- LVDS0 + LVDS1:
 none
 echo 0 > /sys/class/graphics/fb2/blank

Signed-off-by: Lily Zhang <r58066@freescale.com>