[AArch64][SME] Refactor MachineSMEABI pass state (NFCI) (#156674)

This removes the pass state (aside from target classes) from the
MachineSMEABI class, and instead passes/returns state between functions.

The intention is to make dataflow (and where state is mutated) more
apparent.

Author: MacDue

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -9312,6 +9312,7 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   std::optional<unsigned> ZAMarkerNode;
   bool UseNewSMEABILowering = getTM().useNewSMEABILowering();
+
   if (UseNewSMEABILowering) {
     if (CallAttrs.requiresLazySave() ||
         CallAttrs.requiresPreservingAllZAState())