trivial: netns: fix typo in 'struct net.passive' description

Replace 'decided' with 'decide' so that comment would be

/* To decide when the network namespace should be freed. */
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/net_namespace.h

@@ -52,7 +52,7 @@ struct bpf_prog;
 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
 
 struct net {
-	refcount_t		passive;	/* To decided when the network
+	refcount_t		passive;	/* To decide when the network
 						 * namespace should be freed.
 						 */
 	refcount_t		count;		/* To decided when the network