ARM: dts: bcm2835: Use the L2 non-allocating alias

The /soc/dma-ranges property on BCM2835 currently results in DMA
addresses in the range 0x40000000-0x5fffffff. This will allocate in the
system L2 cache, which may adversely affect performance.

Change the dma-ranges property to give addresses in the range
0x80000000-0x9fffffff, which are coherent with L2 but non-allocating.

See: https://github.com/raspberrypi/linux/issues/3602



Signed-off-by: Phil Elwell <phil@raspberrypi.com>