render/egl: don't rely on being able to open primary node
render/egl: don't rely on being able to open primary node

On some setups (e.g. remote access via SSH) the current user won't have
the permission to open the primary node at all. It's still possible to
use drmGetDevices to match the primary node name returned by EGL.

Closes: https://github.com/swaywm/wlroots/issues/2488

SirCmpwn/wlroots,swaywm/wlroots,swaywm/wlroots