imx93_evk: add back Low drive mode ddr timing file

Add back low drive mode 1866mts ddr timing file, no need
CONFIG_IMX9_LOW_DRIVE_MODE anymore, using runtime selection.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/freescale/imx93_evk/spl.c b/board/freescale/imx93_evk/spl.c
index 503286c..a214c04 100644
--- a/board/freescale/imx93_evk/spl.c
+++ b/board/freescale/imx93_evk/spl.c
@@ -52,9 +52,16 @@
 	puts("Normal Boot\n");
 }
 
+extern struct dram_timing_info dram_timing_1866mts;
 void spl_dram_init(void)
 {
-	ddr_init(&dram_timing);
+	struct dram_timing_info *ptiming = &dram_timing;
+
+	if (is_voltage_mode(VOLT_LOW_DRIVE))
+		ptiming = &dram_timing_1866mts;
+
+	printf("DDR: %uMTS\n", ptiming->fsp_msg[0].drate);
+	ddr_init(ptiming);
 }
 
 #if CONFIG_IS_ENABLED(DM_PMIC_PCA9450)