For all users fix or add the error check.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

In order to properly bring up the system PLLs we need a reliable
clocksource. To break the circular dependency between the clocksource
and the CAR driver, get the OSC frequency with a lowlevel function.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Replace the ad-hoc clocksource implementation with a proper driver for
the Tegra 20 timer. This driver is able to do the required hardware
initialisation itself.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Tested-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>