ASoC: rt5514: Revert Hotword Model control

This reverts commit eb33869c ("ASoC: rt5514: Guard Hotword Model bytes
loading") and commit d18420b0

 ("ASoC: rt5514: expose Hotword Model
control")

It is discouraged to use SND_SOC_BYTES_TLV to load arbitrary bytes from
userspace to driver. Removing the 'Hotword Model' control until we have
a good way to verify the content of hotword model blobs.

Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Mark Brown <broonie@kernel.org>