irda: Delete an unnecessary check before the function call "irlmp_unregister_service"

The irlmp_unregister_service() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/irda/af_irda.c

@@ -2123,7 +2123,6 @@ static int irda_setsockopt(struct socket *sock, int level, int optname,
 		}
 
 		/* Unregister any old registration */
-		if (self->skey)
 		irlmp_unregister_service(self->skey);
 
 		self->skey = irlmp_register_service((__u16) opt);