realtek: Switch DGS-1210-10P DTS to gpio.dtsi

realtek: Switch DGS-1210-10P DTS to gpio.dtsi

The DTS file for the DGS-1210-10P is slightly different from the other
DGS-1210 devices, in that it didn't specify a gpio-restart node when it
was added. The gpio-restart has been found to work on the DGS-1210-10P
as well, so switch it over to the common definitions.

This converts the last device from the product family to the common
definition for the (external) GPIOs.

Tested-by: Michel Thill <jmthill@gmail.com>
Signed-off-by: Sander Vanheule <sander@svanheule.net>
(cherry picked from commit 7c0d1c1eb10a7040af6478742dd053f40b24a467)