ASoC: SOF: PM: rename sof_send_pm_ipc to sof_send_pm_ctx_ipc

The helper sof_send_pm_ipc() is only suitable for context save/restore
IPCs' sending, so rename it to sof_send_pm_ctx_ipc here.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191025224122.7718-13-pierre-louis.bossart@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>