Each link has separate power controls, but experimental results show
we need to use an all-or-none approach to the link power management.

This change has marginal power impacts, the DSP needs to be powered
anyways before SoundWire links can be powered, and even when powered a
link can be in clock-stopped mode.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200901150556.19432-11-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>