nfs: propagate devname to nfs{,4}_get_root()

step 1 of ->mnt_devname fixes: make sure we have the value of devname
available in ..._get_root().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index b5ffe8f..4d6e5a3 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -75,7 +75,8 @@
 /*
  * get an NFS2/NFS3 root dentry from the root filehandle
  */
-struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
+			    const char *devname)
 {
 	struct nfs_server *server = NFS_SB(sb);
 	struct nfs_fsinfo fsinfo;
@@ -169,7 +170,8 @@
 /*
  * get an NFS4 root dentry from the root filehandle
  */
-struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
+			     const char *devname)
 {
 	struct nfs_server *server = NFS_SB(sb);
 	struct nfs_fattr *fattr = NULL;