o Rewrite softdma_process_tx() of Altera SoftDMA engine driver
so it does not require a bounce buffer. The only need for this was to align the buffer address. Implement unaligned access and we don't need to copy data twice.
o Remove contigmalloc-based bounce buffer from xDMA code since it is
not suitable for arbitrary memory provided by platform, which is sometimes a dedicated piece of memory that is not managed by OS at all.
Sponsored by: DARPA, AFRL