drm/amd/display: Only set PSR version when valid

[Why]
DMCUB will hang if we send a PSR unsupported set version command.

This can occur if we fall-through into the default case in the switch
statement for PSR version.

[How]
Add an unsupported check after the switch statement.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -138,6 +138,10 @@ static bool dmub_psr_set_version(struct dmub_psr *dmub, struct dc_stream_state *
 		cmd.psr_set_version.psr_set_version_data.version = PSR_VERSION_UNSUPPORTED;
 		break;
 	}
+
+	if (cmd.psr_set_version.psr_set_version_data.version == PSR_VERSION_UNSUPPORTED)
+		return false;
+
 	cmd.psr_set_version.psr_set_version_data.cmd_version = DMUB_CMD_PSR_CONTROL_VERSION_1;
 	cmd.psr_set_version.psr_set_version_data.panel_inst = panel_inst;
 	cmd.psr_set_version.header.payload_bytes = sizeof(struct dmub_cmd_psr_set_version_data);