driver core: drivers/base/sys.c: update comments

There are no functions named sys_device_shutdown or sys_device_suspend
in the kernel.
They should be fixed to sysdev_shutdown and sysdev_suspend respectively.

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>