staging: wimax: i2400m: add space before open parenthesis

fixing ERROR: space required before the open parenthesis '('
Signed-off-by: Rajesh Kumbhakar <sssraj.sssraj@gmail.com>
Link: https://lore.kernel.org/r/20210221133951.21234-1-sssraj.sssraj@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wimax/i2400m/netdev.c

@@ -523,7 +523,7 @@ void i2400m_net_erx(struct i2400m *i2400m, struct sk_buff *skb,
 
 	d_fnstart(2, dev, "(i2400m %p skb %p [%u] cs %d)\n",
 		  i2400m, skb, skb->len, cs);
-	switch(cs) {
+	switch (cs) {
 	case I2400M_CS_IPV4_0:
 	case I2400M_CS_IPV4:
 		i2400m_rx_fake_eth_header(i2400m->wimax_dev.net_dev,