perf_counter tools: fix build error

ctype.h crawled out of the bit bucket :)
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Documentation/perf_counter/builtin-record.c

@@ -15,7 +15,6 @@
 #include <fcntl.h>
 #include <stdio.h>
 #include <errno.h>
-#include <ctype.h>
 #include <time.h>
 #include <sched.h>
 #include <pthread.h>