west: blobs: prefer constants to literals for blob status

Replace blob status literals with the corresponding
constants defined in zephyr_module.

Signed-off-by: Christophe Dufaza <chris@openmarl.org>
diff --git a/scripts/zephyr_module.py b/scripts/zephyr_module.py
index 20955cd..93928f6 100755
--- a/scripts/zephyr_module.py
+++ b/scripts/zephyr_module.py
@@ -345,7 +345,7 @@
 
 def process_kconfig(module, meta):
     blobs = process_blobs(module, meta)
-    taint_blobs = len(tuple(filter(lambda b: b['status'] != 'D', blobs))) != 0
+    taint_blobs = any(b['status'] != BLOB_NOT_PRESENT for b in blobs)
     section = meta.get('build', dict())
     module_path = PurePath(module)
     module_yml = module_path.joinpath('zephyr/module.yml')