If applespi is enabled, but LEDs class support is not, the build fails:

drivers/input/keyboard/applespi.o: In function `applespi_probe':
applespi.c:(.text+0x1fcd): undefined reference to `devm_led_classdev_register_ext'

Add "depends on LEDS_CLASS" to the Konfig
Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 038b1a05 ("Input: add Apple SPI keyboard and trackpad driver")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>