ASoC: wm_hubs: Add missing break in hp_supply_event()

commit 268ff145 upstream.

Spotted by coverity CID 115170.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>