The timings of the poller calling have changed, digging out
a latent bug in pxa27x udc controller.
The polling routine is called before the probe function is
called, and the driver internal are not initialized at that
time. This triggers a NULL pointer exception.

Fix it by moving poller registration after driver probe.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>