Rewrite Dolphin audio to use libogc's standard ASND API

Replaces the ansnd-based backend (a third-party library with a custom
DSP ucode Dolphin's HLE audio emulation doesn't recognize, requiring
-a LLE as a workaround) with libogc's own asndlib - the standard,
HLE-supported audio API most GC/Wii homebrew already uses.

Also fixes three real bugs found while getting a large (41MB) WAV
asset actually playing on Dolphin:

- audiostreamdolphin.c previously buffered a stream's entire loop
  segment into one allocation up front (inherited from the ansnd
  design) - fine for a short test tone, but an out-of-memory crash for
  a real multi-minute track on GameCube's 24MB (or even Wii's 88MB)
  total RAM. Rewritten to stream bounded windows via ASND's real
  double-buffer primitives (ASND_SetVoice + ASND_AddVoice, polled from
  the main thread - never from an interrupt callback), matching how
  Linux/PSP already work.

- ASND_TestVoiceBufferReady() returns SND_OK (0) when ready and
  SND_BUSY (1) when not, in the actual toolchain fork
  (extremscorner/libogc2) this project builds against - opposite of a
  plain boolean. Treating the raw result as one meant a genuinely
  ready voice's SND_OK read as false, silently skipping every
  ASND_AddVoice() call forever after a stream's first buffered window.

- audioStreamPcmRead()'s 16-bit fast path read WAV's little-endian
  sample bytes straight into the output buffer with no byte-swap -
  correct by coincidence on every little-endian platform this engine
  targets (Linux, PSP), but reversed every sample's bytes on
  Dolphin/GameCube/Wii's big-endian PowerPC.

libmad is GPL-licensed (see audiostreammp3decodersw.h's own note from
the prior MP3 change); libogc's asndlib is under a permissive
BSD-style license, so this doesn't add another such dependency.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

cmake/targets/dolphin.cmake

@@ -61,7 +61,7 @@ target_link_libraries(${DUSK_LIBRARY_TARGET_NAME} PRIVATE
   zstd
   z
   lzma
-  ansnd
+  asnd
   mad
 )