net: qcom/emac: make function emac_isr static

The function emac_isr is local to the source and does not need to
be in global scope, so make it static.

Cleans up sparse warnings:
symbol 'emac_isr' was not declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/qualcomm/emac/emac.c

@@ -130,7 +130,7 @@ static int emac_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 	return emac_mac_tx_buf_send(adpt, &adpt->tx_q, skb);
 }
 
-irqreturn_t emac_isr(int _irq, void *data)
+static irqreturn_t emac_isr(int _irq, void *data)
 {
 	struct emac_irq *irq = data;
 	struct emac_adapter *adpt =