The Silicon Image 3114 is the four-port counterpart to the 3112.  It has 
a magic "make all four ports work" bit that must be set, in order to 
receive interrupts from all four ports.  This bit, annoyingly, was 
placed in a register that software has traditionally chosen to 
unconditionally zero.  Doh.

The attached patch sets/clears only the bits we care about, which 
deviates from legacy software, but is arguably better behavior.

The patch shuffles, but does not add, IOs in the dma-start path.  And it 
adds one IO, a read, to the dma-stop path.  This affects everybody, so 
testing of this patch on -any- libata-supported hardware would be 
appreciated.

	Jeff