ASoC: samsung: Makefile cleanup

Commit a076d418 ("ASoC: samsung: Drop AC97 drivers") removed some
unused code and the associated Kconfig options, but left those options
referenced in the Makefile.  Remove the leftover references in the
Makefile.

Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>