fix(imx8m): correct the rank info get fro mstr

the bitfield of active_ranks in MSTR is defined as below.
Correct the rank num get in dram_info.

  0x01: one rank;
  0x11: two rank;

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Anson Huang <anson.huang@nxp.com>
Change-Id: Idcadb39f492a8fe81c973ac4136d9a1eaa32f54b
diff --git a/plat/imx/imx8m/ddr/dram.c b/plat/imx/imx8m/ddr/dram.c
index 8ea9ba1..0b0a527 100644
--- a/plat/imx/imx8m/ddr/dram.c
+++ b/plat/imx/imx8m/ddr/dram.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 NXP
+ * Copyright 2019-2023 NXP
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -129,7 +129,8 @@
 	ddrc_mstr = mmio_read_32(DDRC_MSTR(0));
 
 	dram_info.dram_type = ddrc_mstr & DDR_TYPE_MASK;
-	dram_info.num_rank = (ddrc_mstr >> 24) & ACTIVE_RANK_MASK;
+	dram_info.num_rank = ((ddrc_mstr >> 24) & ACTIVE_RANK_MASK) == 0x3 ?
+		DDRC_ACTIVE_TWO_RANK : DDRC_ACTIVE_ONE_RANK;
 
 	/* Get current fsp info */
 	current_fsp = mmio_read_32(DDRC_DFIMISC(0)) & 0xf;
diff --git a/plat/imx/imx8m/include/dram.h b/plat/imx/imx8m/include/dram.h
index ad11a27..c9f18e8 100644
--- a/plat/imx/imx8m/include/dram.h
+++ b/plat/imx/imx8m/include/dram.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 NXP
+ * Copyright 2019-2023 NXP
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -20,6 +20,8 @@
 #define DDRC_DDR3L		BIT(0)
 #define DDR_TYPE_MASK		U(0x3f)
 #define ACTIVE_RANK_MASK	U(0x3)
+#define DDRC_ACTIVE_ONE_RANK	U(0x1)
+#define DDRC_ACTIVE_TWO_RANK	U(0x2)
 
 /* reg & config param */
 struct dram_cfg_param {