Common, DSP: Only compile in x86-64 emitter related utilities on x86 platforms

Previously these were required to be built into the executable so that
the JIT portion of the DSP code would build properly, as the
x86-64-specifics were tightly coupled to the DSP common code. As this is
no longer the case, this is no longer necessary.

Source/Core/Core/CMakeLists.txt

@@ -60,17 +60,6 @@ add_library(core
   DSP/Interpreter/DSPIntMultiplier.cpp
   DSP/Interpreter/DSPIntTables.cpp
   DSP/Jit/DSPEmitterBase.cpp
-  DSP/Jit/x64/DSPEmitter.cpp
-  DSP/Jit/x64/DSPJitRegCache.cpp
-  DSP/Jit/x64/DSPJitExtOps.cpp
-  DSP/Jit/x64/DSPJitBranch.cpp
-  DSP/Jit/x64/DSPJitCCUtil.cpp
-  DSP/Jit/x64/DSPJitArithmetic.cpp
-  DSP/Jit/x64/DSPJitLoadStore.cpp
-  DSP/Jit/x64/DSPJitMisc.cpp
-  DSP/Jit/x64/DSPJitMultiplier.cpp
-  DSP/Jit/x64/DSPJitTables.cpp
-  DSP/Jit/x64/DSPJitUtil.cpp
   FifoPlayer/FifoAnalyzer.cpp
   FifoPlayer/FifoDataFile.cpp
   FifoPlayer/FifoPlaybackAnalyzer.cpp
@@ -235,6 +224,17 @@ add_library(core
 
 if(_M_X86)
   target_sources(core PRIVATE
+    DSP/Jit/x64/DSPEmitter.cpp
+    DSP/Jit/x64/DSPJitRegCache.cpp
+    DSP/Jit/x64/DSPJitExtOps.cpp
+    DSP/Jit/x64/DSPJitBranch.cpp
+    DSP/Jit/x64/DSPJitCCUtil.cpp
+    DSP/Jit/x64/DSPJitArithmetic.cpp
+    DSP/Jit/x64/DSPJitLoadStore.cpp
+    DSP/Jit/x64/DSPJitMisc.cpp
+    DSP/Jit/x64/DSPJitMultiplier.cpp
+    DSP/Jit/x64/DSPJitTables.cpp
+    DSP/Jit/x64/DSPJitUtil.cpp
     PowerPC/Jit64/FPURegCache.cpp
     PowerPC/Jit64/GPRRegCache.cpp
     PowerPC/Jit64/Jit64_Tables.cpp