realtek: remove duplicate '/dts-v1/;' identifier

The identifier is already present in rtl838x.dtsi, and adding it
twice is not only redundant but actually wrong.

Signed-off-by: Adrian Schmutzler <[email protected]>

target/linux/realtek/dts/rtl8380_netgear_gs110tpp-v1.dts

@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-/dts-v1/;
 
 #include "rtl838x.dtsi"
 

target/linux/realtek/dts/rtl8380_zyxel_gs1900-10hp.dts

@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-/dts-v1/;
 
 #include "rtl838x.dtsi"