arm64: dts: ls1028a-rdb: update copyright

Company policy requires that copyright is updated when a file is
touched. Keeping the copyright change separate to reduce the noise in
other patches.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts

@@ -2,7 +2,7 @@
 /*
  * Device Tree file for NXP LS1028A RDB Board.
  *
- * Copyright 2018 NXP
+ * Copyright 2018-2021 NXP
  *
  * Harninder Rai <harninder.rai@nxp.com>
  *