sh_eth: Use bool as return type of sh_eth_is_gether()

Return a boolean from sh_eth_is_gether() and refactor it as a one-liner.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/sh_eth.c

@@ -309,12 +309,9 @@ static const u16 sh_eth_offset_fast_sh3_sh2[SH_ETH_MAX_REGISTER_OFFSET] = {
 	[TSU_ADRL31]	= 0x01fc,
 };
 
-static int sh_eth_is_gether(struct sh_eth_private *mdp)
+static bool sh_eth_is_gether(struct sh_eth_private *mdp)
 {
-	if (mdp->reg_offset == sh_eth_offset_gigabit)
-		return 1;
-	else
-		return 0;
+	return mdp->reg_offset == sh_eth_offset_gigabit;
 }
 
 static void sh_eth_select_mii(struct net_device *ndev)