[LLD][COFF][NFC] Use getMachineArchType helper. (#87495)

It's similar to #87370, but for lld-link.
diff --git a/lld/COFF/Chunks.cpp b/lld/COFF/Chunks.cpp
index 39f4575..004d710 100644
--- a/lld/COFF/Chunks.cpp
+++ b/lld/COFF/Chunks.cpp
@@ -437,19 +437,17 @@
   // Compute the RVA of the relocation for relative relocations.
   uint64_t p = rva + rel.VirtualAddress;
   uint64_t imageBase = file->ctx.config.imageBase;
-  switch (getMachine()) {
-  case AMD64:
+  switch (getArch()) {
+  case Triple::x86_64:
     applyRelX64(off, rel.Type, os, s, p, imageBase);
     break;
-  case I386:
+  case Triple::x86:
     applyRelX86(off, rel.Type, os, s, p, imageBase);
     break;
-  case ARMNT:
+  case Triple::thumb:
     applyRelARM(off, rel.Type, os, s, p, imageBase);
     break;
-  case ARM64:
-  case ARM64EC:
-  case ARM64X:
+  case Triple::aarch64:
     applyRelARM64(off, rel.Type, os, s, p, imageBase);
     break;
   default:
@@ -516,27 +514,25 @@
 }
 
 static uint8_t getBaserelType(const coff_relocation &rel,
-                              llvm::COFF::MachineTypes machine) {
-  switch (machine) {
-  case AMD64:
+                              Triple::ArchType arch) {
+  switch (arch) {
+  case Triple::x86_64:
     if (rel.Type == IMAGE_REL_AMD64_ADDR64)
       return IMAGE_REL_BASED_DIR64;
     if (rel.Type == IMAGE_REL_AMD64_ADDR32)
       return IMAGE_REL_BASED_HIGHLOW;
     return IMAGE_REL_BASED_ABSOLUTE;
-  case I386:
+  case Triple::x86:
     if (rel.Type == IMAGE_REL_I386_DIR32)
       return IMAGE_REL_BASED_HIGHLOW;
     return IMAGE_REL_BASED_ABSOLUTE;
-  case ARMNT:
+  case Triple::thumb:
     if (rel.Type == IMAGE_REL_ARM_ADDR32)
       return IMAGE_REL_BASED_HIGHLOW;
     if (rel.Type == IMAGE_REL_ARM_MOV32T)
       return IMAGE_REL_BASED_ARM_MOV32T;
     return IMAGE_REL_BASED_ABSOLUTE;
-  case ARM64:
-  case ARM64EC:
-  case ARM64X:
+  case Triple::aarch64:
     if (rel.Type == IMAGE_REL_ARM64_ADDR64)
       return IMAGE_REL_BASED_DIR64;
     return IMAGE_REL_BASED_ABSOLUTE;
@@ -551,7 +547,7 @@
 // Only called when base relocation is enabled.
 void SectionChunk::getBaserels(std::vector<Baserel> *res) {
   for (const coff_relocation &rel : getRelocs()) {
-    uint8_t ty = getBaserelType(rel, getMachine());
+    uint8_t ty = getBaserelType(rel, getArch());
     if (ty == IMAGE_REL_BASED_ABSOLUTE)
       continue;
     Symbol *target = file->getSymbol(rel.SymbolTableIndex);