nfsd: eliminate NFSD_DEBUG

Commit f895b252d4edf ("sunrpc: eliminate RPC_DEBUG") introduced
use of IS_ENABLED() in a uapi header which leads to a build
failure for userspace apps trying to use <linux/nfsd/debug.h>:

   linux/nfsd/debug.h:18:15: error: missing binary operator before token "("
  #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
                ^

Since this was only used to define NFSD_DEBUG if CONFIG_SUNRPC_DEBUG
is enabled, replace instances of NFSD_DEBUG with CONFIG_SUNRPC_DEBUG.

Cc: stable@vger.kernel.org
Fixes: f895b252d4edf "sunrpc: eliminate RPC_DEBUG"
Signed-off-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index 665ef5a..a563ddb 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -31,7 +31,7 @@
 static struct hlist_head	nlm_files[FILE_NRHASH];
 static DEFINE_MUTEX(nlm_file_mutex);
 
-#ifdef NFSD_DEBUG
+#ifdef CONFIG_SUNRPC_DEBUG
 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
 {
 	u32 *fhp = (u32*)f->data;