HID: apple: ensure the keyboard backlight is off if suspending

HID: apple: ensure the keyboard backlight is off if suspending

Some users reported that upon suspending their keyboard backlight
remained on. Fix this by adding the missing LED_CORE_SUSPENDRESUME flag.

Cc: stable@vger.kernel.org
Fixes: 394ba612f941 ("HID: apple: Add support for magic keyboard backlight on T2 Macs")
Fixes: 9018eacbe623 ("HID: apple: Add support for keyboard backlight on certain T2 Macs.")
Reported-by: André Eikmeyer <andre.eikmeyer@gmail.com>
Tested-by: André Eikmeyer <andre.eikmeyer@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>