arm: imx: Use log_err for errors in read_auth_container

To allow for more flexible handling of errors, use log_err instead of
printf.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
diff --git a/arch/arm/mach-imx/parse-container.c b/arch/arm/mach-imx/parse-container.c
index c5df78d..48cffb3 100644
--- a/arch/arm/mach-imx/parse-container.c
+++ b/arch/arm/mach-imx/parse-container.c
@@ -3,6 +3,7 @@
  * Copyright 2018-2021 NXP
  */
 
+#define LOG_CATEGORY LOGC_ARCH
 #include <common.h>
 #include <stdlib.h>
 #include <errno.h>
@@ -85,13 +86,13 @@
 	}
 
 	if (container->tag != 0x87 && container->version != 0x0) {
-		printf("Wrong container header\n");
+		log_err("Wrong container header\n");
 		ret = -ENOENT;
 		goto end;
 	}
 
 	if (!container->num_images) {
-		printf("Wrong container, no image found\n");
+		log_err("Wrong container, no image found\n");
 		ret = -ENOENT;
 		goto end;
 	}