rampis: mt7621: Edgerouter-X update compat version to 2.0

rampis: mt7621: Edgerouter-X update compat version to 2.0

Use compat version to indicate that the new layout for larger kernels
is in place. This handled by the patch to ubnt.sh to always select
the kernel1 slot for flashing and as active kernel slot.

Signed-off-by: Tim Lunn <tim@feathertop.org>
Tested-by: Mauri Sandberg <maukka@ext.kapsi.fi>
Link: https://github.com/openwrt/openwrt/pull/15194
(cherry picked from commit 1bdbd511b27017157e92ffe128e66853d169dcbf)
Link: https://github.com/openwrt/openwrt/pull/17097
Signed-off-by: Petr Štetiar <ynezz@true.cz>