[WIP] DSP: some changes for ARAM ops in wii mode

* The Wii has no ARAM. DMA'ing to/from it via the interface in the DSP MMIO registers doesn't do anything.
* Bump up the ARAM DMA chunk granularity to 32 bytes.
* Stop doing unnecessary byteswaps.
* Remove some special casing when DSP is reading from memory in Wii mode.
* Mask of main memory addrs to turn standard (BAT) mapping addrs into physical memory addrs.
* Make sure all ARAM/RAM/Size parameters are aligned to 32 bytes.
Yes, it can read from both MEM1 and MEM2 but only write to MEM2. For writes the top bit of the accelerator address has to be set (in both GC and wii mode) but that should probably be handled in the DSP core rather than here.