[llvm-readobj] Fix ambiguous call of printNumber in ELFDumper.cpp (NFC)

/Users/jiefu/llvm-project/llvm/tools/llvm-readobj/ELFDumper.cpp:7175:5: error: call to member function 'printNumber' is ambiguous
  W.printNumber("TotalBuckets", NBucket);
  ~~^~~~~~~~~~~
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:201:16: note: candidate function
  virtual void printNumber(StringRef Label, uint64_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:205:16: note: candidate function
  virtual void printNumber(StringRef Label, uint32_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:209:16: note: candidate function
  virtual void printNumber(StringRef Label, uint16_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:213:16: note: candidate function
  virtual void printNumber(StringRef Label, uint8_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:217:16: note: candidate function
  virtual void printNumber(StringRef Label, int64_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:221:16: note: candidate function
  virtual void printNumber(StringRef Label, int32_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:225:16: note: candidate function
  virtual void printNumber(StringRef Label, int16_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:229:16: note: candidate function
  virtual void printNumber(StringRef Label, int8_t Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:237:16: note: candidate function
  virtual void printNumber(StringRef Label, float Value) {
               ^
/Users/jiefu/llvm-project/llvm/include/llvm/Support/ScopedPrinter.h:241:16: note: candidate function
  virtual void printNumber(StringRef Label, double Value) {
               ^