feat(mt8196): fix MT8196 gpio driver

- Add GPIO_BASE in mtgpio.c
- Modify gpio register address

Change-Id: I648473fa373d208fa29c7069637974e097b75b26
diff --git a/plat/mediatek/mt8196/drivers/gpio/mtgpio.c b/plat/mediatek/mt8196/drivers/gpio/mtgpio.c
index 6257159..a34f706 100644
--- a/plat/mediatek/mt8196/drivers/gpio/mtgpio.c
+++ b/plat/mediatek/mt8196/drivers/gpio/mtgpio.c
@@ -23,7 +23,8 @@
 	REG_11,
 	REG_12,
 	REG_13,
-	REG_14
+	REG_14,
+	REG_15
 } RegEnum;
 
 uintptr_t mt_gpio_find_reg_addr(uint32_t pin)
@@ -37,48 +38,51 @@
 
 	switch (gpio_info.base & 0xF) {
 	case REG_0:
-		reg_addr = IOCFG_RT_BASE;
+		reg_addr = GPIO_BASE;
 		break;
 	case REG_1:
-		reg_addr = IOCFG_RM1_BASE;
+		reg_addr = IOCFG_RT_BASE;
 		break;
 	case REG_2:
-		reg_addr = IOCFG_RM2_BASE;
+		reg_addr = IOCFG_RM1_BASE;
 		break;
 	case REG_3:
-		reg_addr = IOCFG_RB_BASE;
+		reg_addr = IOCFG_RM2_BASE;
 		break;
 	case REG_4:
-		reg_addr = IOCFG_BM1_BASE;
+		reg_addr = IOCFG_RB_BASE;
 		break;
 	case REG_5:
-		reg_addr = IOCFG_BM2_BASE;
+		reg_addr = IOCFG_BM1_BASE;
 		break;
 	case REG_6:
-		reg_addr = IOCFG_BM3_BASE;
+		reg_addr = IOCFG_BM2_BASE;
 		break;
 	case REG_7:
-		reg_addr = IOCFG_LT_BASE;
+		reg_addr = IOCFG_BM3_BASE;
 		break;
 	case REG_8:
-		reg_addr = IOCFG_LM1_BASE;
+		reg_addr = IOCFG_LT_BASE;
 		break;
 	case REG_9:
-		reg_addr = IOCFG_LM2_BASE;
+		reg_addr = IOCFG_LM1_BASE;
 		break;
 	case REG_10:
-		reg_addr = IOCFG_LB1_BASE;
+		reg_addr = IOCFG_LM2_BASE;
 		break;
 	case REG_11:
-		reg_addr = IOCFG_LB2_BASE;
+		reg_addr = IOCFG_LB1_BASE;
 		break;
 	case REG_12:
-		reg_addr = IOCFG_TM1_BASE;
+		reg_addr = IOCFG_LB2_BASE;
 		break;
 	case REG_13:
-		reg_addr = IOCFG_TM2_BASE;
+		reg_addr = IOCFG_TM1_BASE;
 		break;
 	case REG_14:
+		reg_addr = IOCFG_TM2_BASE;
+		break;
+	case REG_15:
 		reg_addr = IOCFG_TM3_BASE;
 		break;
 	default: