DSPHLE: Prevent AX GC and AX Wii symbol mixups

Putting AX functions from AXVoice.h in an anonymous namespace does
successfully prevent compilers from merging those functions and
allows us to avoid ODR violations.

However, tools such as gdb still mix up AX GC and AX Wii functions
and variables because those have the exact same symbol names.

This can be fixed by using inline namespaces which are transparent
at the source code level but forces AX GC and AX Wii symbols to be
different.

Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h

@@ -32,8 +32,14 @@ namespace DSP::HLE
 #define MAX_SAMPLES_PER_FRAME 96
 #endif
 
-// Put all of that in an anonymous namespace to avoid stupid compilers merging
+// Use an inline namespace to prevent stupid compilers and debuggers from merging
 // functions from AX GC and AX Wii.
+#ifdef AX_GC
+inline namespace AXGC
+#else
+inline namespace AXWii
+#endif
+{
 namespace
 {
 // Useful macro to convert xxx_hi + xxx_lo to xxx for 32 bits.
@@ -541,4 +547,5 @@ void ProcessVoice(PB_TYPE& pb, const AXBuffers& buffers, u16 count, AXMixControl
 }
 
 }  // namespace
+}  // inline namespace AXGC/AXWii
 }  // namespace DSP::HLE