gbm: Link to libwayland-drm if Wayland EGL platform is enabled

We were relying on libEGL to pull in libwayland-client symbols, but with
commit 2c2e64edaba0f6aeb181ca5b51eb8dea8e9b39f9 cleaned up the
symbol leak.

https://bugs.freedesktop.org/show_bug.cgi?id=67962
3 files changed