drm/amd/pm: Return 0 as default min power limit for legacy asics

Return 0 as the default min power limit for the asics use
powerplay.
Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c

@@ -1022,6 +1022,9 @@ static int pp_get_power_limit(void *handle, uint32_t *limit,
 				*limit /= 100;
 			}
 			break;
+		case PP_PWR_LIMIT_MIN:
+			*limit = 0;
+			break;
 		default:
 			ret = -EOPNOTSUPP;
 			break;