[ELF] Don't call getPPC64TargetInfo outside Driver. NFC

getPPC64TargetInfo should only be called once per link invocation.

Author: MaskRay

lld/ELF/SyntheticSections.cpp

@@ -1571,7 +1571,7 @@ DynamicSection<ELFT>::computeContents() {
   }
 
   if (ctx.arg.emachine == EM_PPC64)
-    addInt(DT_PPC64_OPT, getPPC64TargetInfo(ctx)->ppc64DynamicSectionOpt);
+    addInt(DT_PPC64_OPT, ctx.target->ppc64DynamicSectionOpt);
 
   addInt(DT_NULL, 0);
   return entries;

lld/ELF/Thunks.cpp

@@ -1539,7 +1539,7 @@ static Thunk *addThunkPPC64(Ctx &ctx, RelType type, Symbol &s, int64_t a) {
   // If we are emitting stubs for NOTOC relocations, we need to tell
   // the PLT resolver that there can be multiple TOCs.
   if (type == R_PPC64_REL24_NOTOC)
-    getPPC64TargetInfo(ctx)->ppc64DynamicSectionOpt = 0x2;
+    ctx.target->ppc64DynamicSectionOpt = 0x2;
 
   if (s.isInPlt())
     return type == R_PPC64_REL24_NOTOC