soc/qman: Replace of_get_property() with portable equivalent

Use arch portable of_property_read_u32() instead, which takes
care of endianness conversions.

Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Scott Wood <oss@buserror.net>