wayland/egl: add egl_context to the wayland state

At the moment there are visual glitches when we resize the window. This happens
because in wayland there a special function for resizing EGL windows.

To prevent the glitches move the egl_context to the wayland state in
wayland_common.h and add a new control function to gl_wayland.c to wrap the
vo_wayland_control function to check for resize events.

With the new control wrapper the glitches are gone and the resizing is fluid.