Delete unused function.

set_last_user_activity_timeout() is no longer used or useful.
It opens a sysfs node that no longer exists that used to
be published by a daemon that is no longer even compiled
and that is about to be deleted.  It used to be called
by the power manager with a huge value whose purpose was
essentially to disable the timeout feature altogether.

Long live dead code!

Bug: 6435382
Change-Id: If8f97a66f4e963a11e1c6b67ad97b41b2613043e

include/hardware_legacy/power.h

@@ -33,9 +33,6 @@ enum {
 int acquire_wake_lock(int lock, const char* id);
 int release_wake_lock(const char* id);
 
-// set how long to stay awake after the last user activity in seconds
-int set_last_user_activity_timeout(int64_t delay);
-
 
 #if __cplusplus
 } // extern "C"

power/power.c

@@ -46,8 +46,6 @@ const char * const NEW_PATHS[] = {
     "/sys/power/wake_unlock",
 };
 
-const char * const AUTO_OFF_TIMEOUT_DEV = "/sys/android_power/auto_off_timeout";
-
 //XXX static pthread_once_t g_initialized = THREAD_ONCE_INIT;
 static int g_initialized = 0;
 static int g_fds[OUR_FD_COUNT];
@@ -125,22 +123,3 @@ release_wake_lock(const char* id)
     ssize_t len = write(g_fds[RELEASE_WAKE_LOCK], id, strlen(id));
     return len >= 0;
 }
-
-int
-set_last_user_activity_timeout(int64_t delay)
-{
-//    ALOGI("set_last_user_activity_timeout delay=%d\n", ((int)(delay)));
-
-    int fd = open(AUTO_OFF_TIMEOUT_DEV, O_RDWR);
-    if (fd >= 0) {
-        char buf[32];
-        ssize_t len;
-        len = snprintf(buf, sizeof(buf), "%d", ((int)(delay)));
-        buf[sizeof(buf) - 1] = '\0';
-        len = write(fd, buf, len);
-        close(fd);
-        return 0;
-    } else {
-        return errno;
-    }
-}