powerpc: dts: P1010: Add endianness property to flexcan node

The flexcan driver assumed that flexcan controller is big endian for
powerpc architecture and little endian for other architectures.

But this is not universally true. flexcan controller can be little or
big endian on any architecture.

Therefore the flexcan driver has been modified to check for "big-endian"
device tree property for controllers that are big endian.

consequently add the property to freescale P1010 SOC device tree.

Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Reviewed-by: Poonam Aggrwal <poonam.aggrwal@nxp.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>