Fallback unsupported database SPU decoder on ARM64

[cicerohellmann]

Summary

• fall back from database-applied SPU Decoder: Recompiler (ASMJIT) to Recompiler (LLVM) on ARM64 builds during boot
• log the fallback in fixup_settings() instead of letting SPU initialization fail later

Problem

Need for Speed: Most Wanted [BLES01659] receives SPU Decoder: Recompiler (ASMJIT) from the config database. On ARM64 builds that decoder is unsupported, which caused RPCS3 to abort during SPU initialization with Unsupported spu decoder while the UI remained on the loading screen.

Validation

• built RPCS3 locally on macOS Apple Silicon
• booted BLES01659 through the database config path with the custom per-game override temporarily removed
• verified the log now shows the ARM64 fallback warning and SPU Decoder: Recompiler (LLVM) instead of the previous fatal error
• observed the title proceed past the old boot blocker into active RSX program compilation

[elad335]

You should fallback to SPU dynamic Interpreter instead.