wayland-egl: Don't trust EGL implementations to resize EGL window surfac...

...es

Apparently in some EGL implementations surface caching manages to ignore
surface resizes, so it is safer to re-create the EGL window surface upon
window resizes. This should not impose a big performance issue as resizes
are relatively rare and usually one-time operations.

Signed-off-by: Kalle Vahlman <kalle.vahlman@movial.com>