perf strlist: load() should return a negative errno

To match what its users return.

Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/strlist.c

···
 	FILE *fp = fopen(filename, "r");
 
 	if (fp == NULL)
-		return errno;
+		return -errno;
 
 	while (fgets(entry, sizeof(entry), fp) != NULL) {
 		const size_t len = strlen(entry);