feat(mt8188): add devapc setting of apusys rcx

Apusys rcx is a subsys in apusys, and it is a basic domain of APU and
it connects several components in APU.
The devapc control of apusys rcx is also inside APU and it can only be
set when APU is powered on.
Then apusys kernel driver will trigger rcx devapc init by ATF smc call.

Change-Id: If4249f22a08690b1e4f5aa5f0cbfb54ccacf90e1
diff --git a/plat/mediatek/drivers/apusys/apusys.c b/plat/mediatek/drivers/apusys/apusys.c
index 1aaf7cc..aa2c900 100644
--- a/plat/mediatek/drivers/apusys/apusys.c
+++ b/plat/mediatek/drivers/apusys/apusys.c
@@ -50,6 +50,9 @@
 	case MTK_APUSYS_KERNEL_OP_APUSYS_RV_STOP_MP:
 		ret = apusys_kernel_apusys_rv_stop_mp();
 		break;
+	case MTK_APUSYS_KERNEL_OP_DEVAPC_INIT_RCX:
+		ret = apusys_devapc_rcx_init();
+		break;
 	default:
 		ERROR(MODULE_TAG "%s unknown request_ops = %x\n", MODULE_TAG, request_ops);
 		break;