Flag to disable packing of fetched files into SWU

Add INHIBIT_SWUPDATE_ADD_SRC_URI that disable to pack automatically all
files fetched into the SWU. This is useful when some files are required
to build the image, but they should not deployed. When
INHIBIT_SWUPDATE_ADD_SRC_URI is set, no fetched file is added to SWU.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Stefano Babic <sbabic@denx.de>

classes/swupdate-common.bbclass

@@ -296,8 +296,6 @@ def swupdate_add_src_uri(d, list_for_cpio):
 
     s = d.getVar('S', True)
 
-    if d.getVar('SWUPDATE_SIGNING', True):
-        list_for_cpio.append('sw-description.sig')
     fetch = bb.fetch2.Fetch([], d)
 
     # Add files listed in SRC_URI to the swu file
@@ -386,8 +384,13 @@ python do_swuimage () {
     imgdeploydir = d.getVar('SWUDEPLOYDIR', True)
     shutil.copyfile(os.path.join(workdir, "sw-description"), os.path.join(s, "sw-description"))
 
+    if d.getVar('SWUPDATE_SIGNING', True):
+        list_for_cpio.append('sw-description.sig')
+
     # Add artifacts added via SRC_URI
-    swupdate_add_src_uri(d, list_for_cpio)
+    if not d.getVar('INHIBIT_SWUPDATE_ADD_SRC_URI', True):
+        swupdate_add_src_uri(d, list_for_cpio)
+
     # Add artifacts set via SWUPDATE_IMAGES
     swupdate_add_artifacts(d, list_for_cpio)