net: stmmac: replace unsigned by u32

checkpatch complains about two unsigned without type after.
Since the value return is u32, it is simpler to replace it by u32 instead
of "unsigned int"
Signed-off-by: NCorentin Labbe <clabbe.montjoie@gmail.com>
Acked-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -187,7 +187,7 @@ static void print_pkt(unsigned char *buf, int len)
 
 static inline u32 stmmac_tx_avail(struct stmmac_priv *priv)
 {
-	unsigned avail;
+	u32 avail;
 
 	if (priv->dirty_tx > priv->cur_tx)
 		avail = priv->dirty_tx - priv->cur_tx - 1;
@@ -199,7 +199,7 @@ static inline u32 stmmac_tx_avail(struct stmmac_priv *priv)
 
 static inline u32 stmmac_rx_dirty(struct stmmac_priv *priv)
 {
-	unsigned dirty;
+	u32 dirty;
 
 	if (priv->dirty_rx <= priv->cur_rx)
 		dirty = priv->cur_rx - priv->dirty_rx;