drm/amd/display: wait for set pipe mcp command completion

[Why]
When the driver sends a pipe set command to the DMCU FW, it does not wait
for the command to complete. This can lead to unpredictable behavior if,
for example, the driver were to request a pipe disable to the FW via MCP,
then power down some hardware before the firmware has completed processing
the command.

[How]
Wait for the DMCU FW to finish processing set pipe commands
Signed-off-by: Josip Pavic <Josip.Pavic@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_abm.c

@@ -77,6 +77,9 @@ static bool dce_abm_set_pipe(struct abm *abm, uint32_t controller_id)
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
 
+	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
+			1, 80000);
+
 	return true;
 }