feat(plat/mediatek/mpu): add MPU support for DSP

Forbidden domain D4(DSP) access 0x40000000~0x1FFFF0000.
Signed-off-by: Jiaxin Yu <jiaxin.yu@mediatek.com>
Change-Id: If409df10cecbcccc493d7958ab2765fd110d9009

plat/mediatek/mt8192/drivers/emi_mpu/emi_mpu.c

@@ -117,7 +117,7 @@ void emi_mpu_init(void)
 			      NO_PROT, FORBIDDEN, FORBIDDEN, NO_PROT);
 	emi_mpu_set_protection(&region_info);
 
-	/* Forbidden All */
+	/* DSP protect address */
 	region_info.start = 0x40000000ULL;	/* dram base addr */
 	region_info.end = 0x1FFFF0000ULL;
 	region_info.region = 3;
@@ -128,6 +128,17 @@ void emi_mpu_init(void)
 			      FORBIDDEN, FORBIDDEN, FORBIDDEN, NO_PROT);
 	emi_mpu_set_protection(&region_info);
 
+	/* Forbidden All */
+	region_info.start = 0x40000000ULL;	/* dram base addr */
+	region_info.end = 0x1FFFF0000ULL;
+	region_info.region = 4;
+	SET_ACCESS_PERMISSION(region_info.apc, 1,
+			      FORBIDDEN, FORBIDDEN, FORBIDDEN, FORBIDDEN,
+			      FORBIDDEN, FORBIDDEN, FORBIDDEN, FORBIDDEN,
+			      FORBIDDEN, FORBIDDEN, FORBIDDEN, FORBIDDEN,
+			      FORBIDDEN, FORBIDDEN, FORBIDDEN, NO_PROT);
+	emi_mpu_set_protection(&region_info);
+
 	dump_emi_mpu_regions();
 }