NFSv4: cleanup remove unused nfs4_xdev_fs_type

commit e8f25e6d "NFS: Remove the NFS v4 xdev mount function"
removed the last use of this.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/internal.h

@@ -395,7 +395,6 @@ extern const struct super_operations nfs_sops;
 extern struct file_system_type nfs_fs_type;
 extern struct file_system_type nfs_xdev_fs_type;
 #if IS_ENABLED(CONFIG_NFS_V4)
-extern struct file_system_type nfs4_xdev_fs_type;
 extern struct file_system_type nfs4_referral_fs_type;
 #endif
 bool nfs_auth_info_match(const struct nfs_auth_info *, rpc_authflavor_t);