ARM: mvebu: enable SPI for helios4 and sata and uart images for clearfog

[dgilmore at redhat.com]

In an effort to build SPI images for clearfog and helios4 I needed to make some
minor changes to the dts and Kconfig for the helios4 and set some variables for
UART and SATA images for ClearFog.

Version 2 dropped changes for db-mv784mp-gp as the board turns out to be currently
broken, the serial port is not available and the system bails after loading the SPL
the dts changes for the helios4 have been shrunk back to remove everything not
needed or valid

Dennis