[ARM] Orion: add 88F6183 (Orion-1-90) support

The Orion-1-90 (88F6183) is another member of the Orion SoC family,
which has a 16 bit DDR2 interface, one x1 PCIe port (configurable as
Root Complex or Endpoint), one 10/100/1000 ethernet interface, one
USB 2.0 port with PHY, one SPDIF/I2S interface, one SDIO interface,
one TWSI interface, two UARTs, one SPI interface, a NAND controller,
a crypto engine, and a 4-channel DMA engine.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>