ASoC: SOF: amd: Add psp_mbox_ready() and psp_send_cmd() callback

We need to ensure if PSP is mbox ready before and after sending cmd
to PSP over SMN interface. Add method to check MBOX_READY bit of PSP
with some delay over ACP_PSP_TIMEOUT_COUNTER. Replace psp_fw_validate
with new method psp_send_cmd() to send command via psp mailbox.

Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Ajit Kumar Pandey <AjitKumar.Pandey@amd.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220421165820.337207-2-pierre-louis.bossart@linux.intel.com


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