ASoC: samsung: clean makefile about inexistant files

Clean makefile rules about inexistant files.
Thoses files were removed in commit a076d418 ("ASoC: samsung: Drop AC97 drivers")

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>