Add dri2_egl_display_vtbl::swap_interval, set it for each platform, and
let egl_dri2 dispatch eglSwapInterval to that.
This prepares for the EGL platform extensions.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
Chad Versace