Add PXA embedded pulse width modulator support. The PWM can
generate signals from 49.6kHz to 1.625MHz.
The driver is for pxa2xx family. The pxa3xx was not handled yet.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>