leds: rgb: leds-group-multicolor: Allow LEDs to stay on in suspend

If none of the managed LEDs enable LED_CORE_SUSPENDRESUME, then we
shouldn't need to set it here. This makes it possible to use multicolor
groups with GPIO LEDs that enable retain-state-suspended in the device
tree.

Signed-off-by: Aren Moynihan <aren@peacevolution.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Link: https://lore.kernel.org/r/20240206185400.596979-1-aren@peacevolution.org
[Lee: Changed the comment to respect proper grammar]
Signed-off-by: Lee Jones <lee@kernel.org>