[PKTGEN]: Add try_to_freeze()

The pktgen module prevents suspend-to-disk. Fix.

Acked-by: "Michal Piotrowski" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/core/pktgen.c

···
 #include <linux/ioport.h>
 #include <linux/interrupt.h>
 #include <linux/capability.h>
+#include <linux/freezer.h>
 #include <linux/delay.h>
 #include <linux/timer.h>
 #include <linux/list.h>
···
 			pktgen_rem_one_if(t);
 			t->control &= ~(T_REMDEV);
 		}
+
+		try_to_freeze();
 
 		set_current_state(TASK_INTERRUPTIBLE);
 	}