[NFC][lld] Inclusive language: change master file to merged file

[NFC] As part of using inclusive language within the llvm project, this patch
replaces master with merged in these comments.

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D113903

lld/lib/ReaderWriter/MachO/GOTPass.cpp

@@ -121,7 +121,7 @@ class GOTPass : public Pass {
       }
     }
 
-    // Sort and add all created GOT Atoms to master file
+    // Sort and add all created GOT Atoms to merged file
     std::vector<const GOTEntryAtom *> entries;
     entries.reserve(_targetToGOT.size());
     for (auto &it : _targetToGOT)

lld/lib/ReaderWriter/MachO/ShimPass.cpp

@@ -78,7 +78,7 @@ class ShimPass : public Pass {
                 return (l->name() < r->name());
               });
 
-    // Add all shims to master file.
+    // Add all shims to merged file.
     for (const DefinedAtom *shim : shims)
       mergedFile.addAtom(*shim);