Documentation/timers/hpet_example: drop duplicate header files

Documentation/timers/hpet_example.c: fcntl.h is included more than once.
Documentation/timers/hpet_example.c: signal.h is included more than once.
Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/timers/hpet_example.c

@@ -10,7 +10,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <signal.h>
-#include <fcntl.h>
 #include <errno.h>
 #include <sys/time.h>
 #include <linux/hpet.h>
@@ -24,7 +23,6 @@ extern void hpet_read(int, const char **);
 
 #include <sys/poll.h>
 #include <sys/ioctl.h>
-#include <signal.h>
 
 struct hpet_command {
 	char		*command;