samples: philosphers: Fix typo in famous name

Dijkstra not djkstra

Signed-off-by: Tom Burdick <thomas.burdick@intel.com>

samples/philosophers/src/main.c

@@ -147,7 +147,7 @@ void philosopher(void *id, void *unused1, void *unused2)
 
 	int my_id = POINTER_TO_INT(id);
 
-	/* Djkstra's solution: always pick up the lowest numbered fork first */
+	/* Dijkstra's solution: always pick up the lowest numbered fork first */
 	if (is_last_philosopher(my_id)) {
 		my_fork1 = fork(0);
 		my_fork2 = fork(my_id);