ARM: dts: ls1021a-tsn: remove undocumented property "position" from mma8452 node

Property "postion" is not documented in the mma8452 binding.  Remove it
to resolve the error in "make dtbs_check"
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/ls1021a-tsn.dts

@@ -137,7 +137,6 @@ &i2c0 {
 	/* 3 axis accelerometer */
 	accelerometer@1e {
 		compatible = "fsl,fxls8471";
-		position = <0>;
 		reg = <0x1e>;
 	};