powerpc/pseries/dlpar: use rtas_get_sensor()

Instead of making bare calls to get-sensor-state, use
rtas_get_sensor(), which correctly handles busy and extended delay
statuses.

Fixes: ab519a011caa ("powerpc/pseries: Kernel DLPAR Infrastructure")
Signed-off-by: Nathan Lynch <[e-mail]>
Reviewed-by: Laurent Dufour <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/platforms/pseries/dlpar.c

···
 {
 	int dr_status, rc;
 
-	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
-		       DR_ENTITY_SENSE, drc_index);
+	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
 	if (rc || dr_status != DR_ENTITY_UNUSABLE)
 		return -1;
 
···
 {
 	int dr_status, rc;
 
-	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
-		       DR_ENTITY_SENSE, drc_index);
+	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
 	if (rc || dr_status != DR_ENTITY_PRESENT)
 		return -1;
 
···
 {
 	int dr_status, rc;
 
-	rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
-				DR_ENTITY_SENSE, drc_index);
+	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
 	if (rc || dr_status != DR_ENTITY_PRESENT)
 		return -1;