NFS: Remove pnfs_generic_transfer_commit_list()

It's pretty much a duplicate of nfs_scan_commit_list() that also
clears the PG_COMMIT_TO_DS flag.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/write.c

@@ -1052,6 +1052,7 @@ restart:
 			goto restart;
 		}
 		nfs_request_remove_commit_list(req, cinfo);
+		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
 		nfs_list_add_request(req, dst);
 		ret++;
 		if ((ret == max) && !cinfo->dreq)
@@ -1060,6 +1061,7 @@ restart:
 	}
 	return ret;
 }
+EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
 
 /*
  * nfs_scan_commit - Scan an inode for commit requests