Use a MutableArrayRef. NFC.

llvm-svn: 305968
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
index 028c2cb..6d72f11 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
@@ -113,7 +113,7 @@
     return (IsLittleEndian? InfosLE : InfosBE)[Kind - FirstTargetFixupKind];
   }
 
-  void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
+  void applyFixup(const MCFixup &Fixup, MutableArrayRef<char> Data,
                   uint64_t Value, bool IsPCRel, MCContext &Ctx) const override {
     Value = adjustFixupValue(Fixup.getKind(), Value);
     if (!Value) return;           // Doesn't change encoding.