ARM: dts: imx53-mba53: fix fsl,pins for disp1-grp1

According to fsl,imx53-pinctrl.txt, the pin number of DISP1_DAT_21
should be 545, while 543 is IPU_CSI0_D_3.  Along with the change,
one duplication of DISP1_DAT_0 in disp1-grp1 is removed.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>