ASoC: amd: acp: remove acp poweroff function

BIOS invokes ACP Power off sequence based on ACP device state.
Remove redundant code from ACP PCI driver for ACP Power off sequence.

Signed-off-by: Syed Saba Kareem <Syed.SabaKareem@amd.com>
Link: https://lore.kernel.org/r/Message-Id

: <20230622152406.3709231-4-Syed.SabaKareem@amd.com>
Signed-off-by: Mark Brown <broonie@kernel.org>