NFSD: Clean up the show_nf_flags() macro

The flags are defined using C macros, so TRACE_DEFINE_ENUM is
unnecessary.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/trace.h

@@ -692,12 +692,6 @@ DEFINE_CLID_EVENT(confirmed_r);
 /*
  * from fs/nfsd/filecache.h
  */
-TRACE_DEFINE_ENUM(NFSD_FILE_HASHED);
-TRACE_DEFINE_ENUM(NFSD_FILE_PENDING);
-TRACE_DEFINE_ENUM(NFSD_FILE_BREAK_READ);
-TRACE_DEFINE_ENUM(NFSD_FILE_BREAK_WRITE);
-TRACE_DEFINE_ENUM(NFSD_FILE_REFERENCED);
-
 #define show_nf_flags(val)						\
 	__print_flags(val, "|",						\
 		{ 1 << NFSD_FILE_HASHED,	"HASHED" },		\