plat: imx8mq: correct the reg offset of ddr type register

correct the ddr type register's offset.

Signed-off-by: Bai Ping <ping.bai@nxp.com>
(cherry picked from commit fccb3083469a33173b3d455b396875b50e667d85)
diff --git a/plat/imx/imx8mq/ddr/lpddr4_dvfs.c b/plat/imx/imx8mq/ddr/lpddr4_dvfs.c
index bd96bba..7adbf92 100644
--- a/plat/imx/imx8mq/ddr/lpddr4_dvfs.c
+++ b/plat/imx/imx8mq/ddr/lpddr4_dvfs.c
@@ -31,7 +31,7 @@
 
 static inline int get_ddr_type(void)
 {
-	return mmio_read_32(IMX_DDRC_BASE + DDRC_MSTR(0)) & DDR_TYPE_MASK;
+	return mmio_read_32(DDRC_MSTR(0)) & DDR_TYPE_MASK;
 }
 
 void lpddr4_switch_to_3200(void)