Refactor MediaTek platform common code

Refactor MediaTek platform common code for further mt6795 upstream.
diff --git a/plat/mediatek/common/mtk_sip_svc.h b/plat/mediatek/common/mtk_sip_svc.h
index 94a6036..91252d1 100644
--- a/plat/mediatek/common/mtk_sip_svc.h
+++ b/plat/mediatek/common/mtk_sip_svc.h
@@ -42,6 +42,8 @@
 #define MTK_SIP_SVC_VERSION_MAJOR	0x0
 #define MTK_SIP_SVC_VERSION_MINOR	0x1
 
+#define SMC_AARCH64_BIT		0x40000000
+
 /* Number of Mediatek SiP Calls implemented */
 #define MTK_SIP_NUM_CALLS		4
 
@@ -51,10 +53,19 @@
 #define MTK_SIP_PWR_OFF_MTCMOS			0x82000403
 #define MTK_SIP_PWR_MTCMOS_SUPPORT		0x82000404
 
+/* For MTK SMC from Secure OS */
+/* 0x82000000 - 0x820000FF & 0xC2000000 - 0xC20000FF */
+#define MTK_SIP_KERNEL_BOOT_AARCH32		0x82000200
+#define MTK_SIP_KERNEL_BOOT_AARCH64		0xC2000200
+
 /* Mediatek SiP Calls error code */
 enum {
 	MTK_SIP_E_SUCCESS = 0,
-	MTK_SIP_E_INVALID_PARAM = -1
+	MTK_SIP_E_INVALID_PARAM = -1,
+	MTK_SIP_E_NOT_SUPPORTED = -2,
+	MTK_SIP_E_INVALID_RANGE = -3,
+	MTK_SIP_E_PERMISSION_DENY = -4,
+	MTK_SIP_E_LOCK_FAIL = -5
 };
 
 /*