Some architectures (like Blackfin) only implement ppoll (and skip poll).
So add support for it using existing poll code.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Riku Voipio <riku.voipio@nokia.com>