imx8m: ddr_init: Move ddr_init() messages to debug level

Currently inside ddr_init() there is a mix of printf() and debug()
level messages.

Since this type of information is useful for debug purposes,
convert all of them to debug level for consistency.
Signed-off-by: NFabio Estevam <festevam@gmail.com>
Reviewed-by: NPeng Fan <peng.fan@nxp.com>

drivers/ddr/imx/imx8m/ddr_init.c

@@ -24,7 +24,7 @@ void ddr_init(struct dram_timing_info *dram_timing)
 {
 	unsigned int tmp, initial_drate, target_freq;
 
-	printf("DDRINFO: start DRAM init\n");
+	debug("DDRINFO: start DRAM init\n");
 
 	/* Step1: Follow the power up procedure */
 	if (is_imx8mq()) {
@@ -109,7 +109,7 @@ void ddr_init(struct dram_timing_info *dram_timing)
 		tmp = reg32_read(DDRPHY_CalBusy(0));
 	} while ((tmp & 0x1));
 
-	printf("DDRINFO:ddrphy calibration done\n");
+	debug("DDRINFO:ddrphy calibration done\n");
 
 	/* Step15: Set SWCTL.sw_done to 0 */
 	reg32_write(DDRC_SWCTL(0), 0x00000000);
@@ -161,7 +161,7 @@ void ddr_init(struct dram_timing_info *dram_timing)
 
 	/* enable port 0 */
 	reg32_write(DDRC_PCTRL_0(0), 0x00000001);
-	printf("DDRINFO: ddrmix config done\n");
+	debug("DDRINFO: ddrmix config done\n");
 
 	/* save the dram timing config into memory */
 	dram_config_save(dram_timing, CONFIG_SAVED_DRAM_TIMING_BASE);