NFSv4.1: use BITS_PER_LONG macro in nfs4session.h

Use the existing BITS_PER_LONG macro instead of calculating the value.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4session.h

@@ -34,7 +34,7 @@ enum nfs4_slot_tbl_state {
 	NFS4_SLOT_TBL_DRAINING,
 };
 
-#define SLOT_TABLE_SZ DIV_ROUND_UP(NFS4_MAX_SLOT_TABLE, 8*sizeof(long))
+#define SLOT_TABLE_SZ DIV_ROUND_UP(NFS4_MAX_SLOT_TABLE, BITS_PER_LONG)
 struct nfs4_slot_table {
 	struct nfs4_session *session;		/* Parent session */
 	struct nfs4_slot *slots;		/* seqid per slot */