egl: Remove bogus invalidate code.

egl: Remove bogus invalidate code.

The invalidate event support is a careful dance between driver and loader,
where both have to say they can handle it, and then the loader reports
invalidate events for the driver so the driver can do the optimization.

The EGL code doesn't report __DRIuseInvalidateExtension to the driver, so it
has no responsibility to call the driver's invalidate function, and the driver
is doing the glViewport hack because it assume.  This is not
the only time invalidate would need to be called (we need it *any* time an
invalidate event comes down the pipe, but we don't watch for them), so just
stop calling the driver's function.

Acked-by: Chad Versace <chad.versace@linux.intel.com>