This operations should be generic as there is nothing Intel
specific. This works well for NXP i.MX8 stream IPC ops.

We start by moving sof/intel/intel-ipc.c into sof/stream-ipc.c and
rename the functions to be generic.

Notice that we use newly introduced snd_sof_dsp_mailbox_read
instead of sof_mailbox_read, to make sure that we are not
bound to existing MMIO memory access, and we allow platform
to implement their own memory access routines.
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Bud Liviu-Alexandru <budliviu@gmail.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@gmail.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20211004152147.1268978-3-daniel.baluta@oss.nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>