tools: kwbimage: Fix mkimage/dumpimage -l argument

Do not check for kwbimage configuration file when just showing information
about existing kwbimage file.

The check for kwbimage configuration file is required only when creating
kwbimage, not when showing information about image or when extracting data
from image.

With this change, it is possible to call mkimage -l and dumpimage -l also
for existing kwbimage file.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/tools/kwbimage.c b/tools/kwbimage.c
index d159087..9b63ce8 100644
--- a/tools/kwbimage.c
+++ b/tools/kwbimage.c
@@ -2331,7 +2331,8 @@
  */
 static int kwbimage_check_params(struct image_tool_params *params)
 {
-	if (!params->iflag && (!params->imagename || !strlen(params->imagename))) {
+	if (!params->lflag && !params->iflag &&
+	    (!params->imagename || !strlen(params->imagename))) {
 		char *msg = "Configuration file for kwbimage creation omitted";
 
 		fprintf(stderr, "Error:%s - %s\n", params->cmdname, msg);