ramips: overwrite reset gpio properties in DIR-860L DTS

ramips: overwrite reset gpio properties in DIR-860L DTS

As suggested by Sergio, this adds GPIOs 19 and 8 explicitly into the
DIR-860L DTS, so the PCI-E ports get reset and the N radio (radio1)
on PCI-E port 1 comes up reliably.

Fixes the following error that popped up in dmesg:

    [    1.638942] mt7621-pci 1e140000.pcie: pcie1 no card, disable it (RST & CLK)

Suggested-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Stijn Segers <foss@volatilesystems.org>
Reviewed-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>