Refactor DMA function and add responder for WriteFileFromMemory command

The WriteFileFromMemory command transfers data to the BMC from the Host
using DMA. Refactor the DMA transfer function so that the code between
the read and write file commands is common.

Signed-off-by: Eddie James <eajames@us.ibm.com>
Change-Id: I1ce5739c312c4789b882bff04f0e686cc438ab52
5 files changed