wayland_egl: Stop setting swap interval to 0

wayland_egl: Stop setting swap interval to 0

We have some "vsync" variable cargo culted from somewhere that is never
properly set, so is always 0 because it's in a calloced structure.

It's then used to set eglSwapInterval() to 0 always, which results
in mesa using wl_display_sync() instead of wl_surface_frame() for
its frame ready callback mechanism.

Remove it entirely and use the sensible default swapinterval.