DMA: OF: Check properties value before running be32_to_cpup() on it

DMA: OF: Check properties value before running be32_to_cpup() on it

commit 9a188eb126aa7bf27077ee46fcb914898d6fc281 upstream.

In of_dma_controller_register() routine we are calling of_get_property() as an
parameter to be32_to_cpup(). In case the property doesn't exist we will get a
crash.

This patch changes this code to check if we got a valid property first and then
runs be32_to_cpup() on it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Robert Richter <robert.richter@calxeda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>