can: sja1000: fix handling on dt properties on little endian systems

To get correct endianes on little endian cpus (like arm) while reading device
tree properties, this patch replaces of_get_property() with
of_property_read_u32(). While there use of_property_read_bool() for the
handling of the boolean "nxp,no-comparator-bypass" property.

Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>