ASoC: hdmi-codec: Fix module unloading caused kernel crash

The hcp->chmap_info must not be freed up in the hdmi_codec_remove()
function as it leads to kernel crash due ALSA core's
pcm_chmap_ctl_private_free() is trying to free it up again when the card
destroyed via snd_card_free.

Commit cd6111b2

 ("ASoC: hdmi-codec: add channel mapping control")
should not have added the kfree(hcp->chmap_info); to the hdmi_codec_remove
function.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Jyri Sarha <jsarha@ti.com>
Tested-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>