The function hdmi_codec_eld_chmap and arrays hdmi_codec_stereo_chmaps
and hdmi_codec_8ch_chmaps are local to the source and do not need to
be in global scope, so make them static.

Cleans up sparse warnings:
symbol 'hdmi_codec_eld_chmap' was not declared. Should it be static?
symbol 'hdmi_codec_stereo_chmaps' was not declared. Should it be static?
symbol 'hdmi_codec_8ch_chmaps' was not declared. Should it be static?
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>