EGLFS and MinimalEGL windows are not marked as OpenGL surfaces

Several QOpenGLContext methods fails incorrectly on QWindows from EGL or
MinimalEGL. This is happens because they are incorrectly marked as raster
surfaces instead of OpenGL surfaces.

Change-Id: Ic9b3859915a9049fce442216b01dce89521fa5ee
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>