This adds DRAM support to E31x devices. Due to the size of the DDR3
memory controller, it is not enabled by default. You can include the
memory controller IP in the build by adding the DRAM environment
variable to your build. For example:
DRAM=1 make E310_SG3
Original-commit: 788fef11ef890c6dcee3be495fc381bcf2990d3b
Wade Fife
c322899053