mpc85xx: p1010: TL-WDR4900v1: DTS update for RFKILL switch

mpc85xx: p1010: TL-WDR4900v1: DTS update for RFKILL switch

The TL-WDR4900v1, like many other similarly-aged TP-Link devices, is
using a flipswitch for toggling WiFi, not a pushbutton. Update the DTS
to reflect that. The debounce time used here has been chosen based on
other supported (but different target) TP-Link devices that are using
such a flipswitch.

Requires usage of the gpio-button-hotplug driver to work.

Fixes: #13552
Signed-off-by: Shine <4c.fce2@proton.me>
Tested-by: Edward Chow <equu@openmail.cc>
Link: https://github.com/openwrt/openwrt/pull/22494
Signed-off-by: Robert Marko <robimarko@gmail.com>