DSPJit: Suppress offsetof conditionally-supported warnings

The DSP JIT only applies on x64, so if it doesn't work on esoteric compilers then that's not a problem.  (And if it fails to compile, then it'll still produce an error on that platform, just no warnings on other platforms)

Source/Core/Core/DSP/Jit/x64/DSPEmitter.cpp

@@ -470,6 +470,10 @@ void DSPEmitter::CompileDispatcher()
   RET();
 }
 
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Winvalid-offsetof"
+#endif
 Gen::OpArg DSPEmitter::M_SDSP_pc()
 {
   return MDisp(R15, static_cast<int>(offsetof(SDSP, pc)));
@@ -503,5 +507,8 @@ Gen::OpArg DSPEmitter::M_SDSP_reg_stack_ptrs(size_t index)
   return MDisp(R15, static_cast<int>(offsetof(SDSP, reg_stack_ptrs) +
                                      sizeof(SDSP::reg_stack_ptrs[0]) * index));
 }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 
 }  // namespace DSP::JIT::x64

Source/Core/Core/DSP/Jit/x64/DSPJitMultiplier.cpp

@@ -149,7 +149,14 @@ void DSPEmitter::multiply_mulx(u8 axh0, u8 axh1)
 // direct use of prod regs by AX/AXWII (look @that part of ucode).
 void DSPEmitter::clrp(const UDSPInstruction opc)
 {
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Winvalid-offsetof"
+#endif
   int offset = static_cast<int>(offsetof(SDSP, r.prod.val));
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
   // 64bit move to memory does not work. use 2 32bits
   MOV(32, MDisp(R15, offset + 0 * sizeof(u32)), Imm32(0xfff00000U));
   MOV(32, MDisp(R15, offset + 1 * sizeof(u32)), Imm32(0x001000ffU));

Source/Core/Core/DSP/Jit/x64/DSPJitRegCache.cpp

@@ -20,6 +20,10 @@ namespace DSP::JIT::x64
 constexpr std::array<X64Reg, 15> s_allocation_order = {
     {R8, R9, R10, R11, R12, R13, R14, R15, RSI, RDI, RBX, RCX, RDX, RAX, RBP}};
 
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Winvalid-offsetof"
+#endif
 static Gen::OpArg GetRegisterPointer(size_t reg)
 {
   switch (reg)
@@ -95,6 +99,9 @@ static Gen::OpArg GetRegisterPointer(size_t reg)
     return M(static_cast<void*>(nullptr));
   }
 }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 
 #define STATIC_REG_ACCS
 //#undef STATIC_REG_ACCS