Fix for SA-1 side DMA to BWRAM banks 0x41+ (#1687)

DDA was incorrectly capped at 16 bits instead of 24, making DMAs to
BWRAM banks 0x41-43 be sent to the corresponding spot in 0x40 instead.
See [the corresponding bug in
bsnes](bsnes-emu/bsnes#309) for some more
context.

ares/sfc/coprocessor/sa1/dma.cpp

@@ -3,7 +3,7 @@ auto SA1::dmaNormal() -> void {
   while(io.dtc--) {
     n8  data = r.mdr;
     n24 source = io.dsa++;
-    n16 target = io.dda++;
+    n24 target = io.dda++;
 
     if(io.sd == DMA::SourceROM && io.dd == DMA::DestBWRAM) {
       step();