[new uImage] Fix erroneous use of image_get_magic() in fdc/usb cmds

Signed-off-by: Marian Balakowicz <m8@semihalf.com>

common/cmd_fdc.c

@@ -836,7 +836,7 @@ int do_fdcboot (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 		return 1;
 	}
 	hdr = (image_header_t *)addr;
-	if (!image_get_magic (hdr)) {
+	if (!image_check_magic (hdr)) {
 		printf ("Bad Magic Number\n");
 		return 1;
 	}

common/cmd_usb.c

@@ -388,7 +388,7 @@ int do_usbboot (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 	hdr = (image_header_t *)addr;
 
-	if (!image_get_magic (hdr)) {
+	if (!image_check_magic (hdr)) {
 		printf("\n** Bad Magic Number **\n");
 		return 1;
 	}