drivers/net: return operator cleanup

Change "return (EXPR);" to "return EXPR;"

return is not a function, parentheses are not required.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/slip.c b/drivers/net/slip.c
index 38547a8..86cbb9e 100644
--- a/drivers/net/slip.c
+++ b/drivers/net/slip.c
@@ -944,7 +944,7 @@
 		}
 	}
 	*ptr++ = END;
-	return (ptr - d);
+	return ptr - d;
 }
 
 static void slip_unesc(struct slip *sl, unsigned char s)