Set LED_CORE_SUSPENDRESUME to LED cdev flags, so that the LED core
would store and restore the LED status at suspend/resume.

In theory, the codec driver should be responsible for all LED bits,
but this might be safer and cover the overlooked cases.
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20200618110842.27238-14-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>