board: rockchip: rk35xx: Add device tree files to MAINTAINERS

Update MAINTAINERS files for RK3566/RK3568/RK3588 boards to include
related device tree files. Also replace space with tabs.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Acked-by: Eugen Hristev <eugen.hristev@collabora.com>
diff --git a/board/radxa/rock5a-rk3588s/MAINTAINERS b/board/radxa/rock5a-rk3588s/MAINTAINERS
index 62fb6b4..0575026 100644
--- a/board/radxa/rock5a-rk3588s/MAINTAINERS
+++ b/board/radxa/rock5a-rk3588s/MAINTAINERS
@@ -4,3 +4,5 @@
 F:	board/radxa/rock5a-rk3588s
 F:	include/configs/rock5a-rk3588s.h
 F:	configs/rock5a-rk3588s_defconfig
+F:	arch/arm/dts/rk3588s-rock-5a.dts
+F:	arch/arm/dts/rk3588s-rock-5a-u-boot.dtsi