kmod-leds-pwm depends on @PWM_SUPPORT, instead of adding pwm to the
features env for specific targets, use the existing detection method.
Signed-off-by: Weikai Kong <priv@pppig236.com>
Link: https://github.com/openwrt/openwrt/pull/18185
Signed-off-by: Robert Marko <robimarko@gmail.com>