perf header: Fix spelling mistake "cant'" -> "can't"

There is a spelling mistake in a warning message. Fix it.

Signed-off-by: Colin King <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/header.c

···
 
 	dir = opendir(path);
 	if (!dir) {
-		pr_warning("failed: cant' open memory sysfs data\n");
+		pr_warning("failed: can't open memory sysfs data\n");
 		return -1;
 	}