platform/x86: int3472/discrete: add LEDS_CLASS dependency

platform/x86: int3472/discrete: add LEDS_CLASS dependency

int3472 now fails to link when the LED support is disabled:

x86_64-linux-ld: drivers/platform/x86/intel/int3472/led.o: in function `skl_int3472_register_pled':
led.c:(.text+0xf4): undefined reference to `led_classdev_register_ext'
x86_64-linux-ld: led.c:(.text+0x131): undefined reference to `led_add_lookup'
x86_64-linux-ld: drivers/platform/x86/intel/int3472/led.o: in function `skl_int3472_unregister_pled':
led.c:(.text+0x16b): undefined reference to `led_remove_lookup'
x86_64-linux-ld: led.c:(.text+0x177): undefined reference to `led_classdev_unregister'

Add an explicit Kconfig dependency.

Fixes: 5ae20a8050d0 ("platform/x86: int3472/discrete: Create a LED class device for the privacy LED")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Link: https://lore.kernel.org/r/20230208163658.2129009-1-arnd@kernel.org
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>