scripts: west: commands: build: fix pylint issue

Do not end except block with a useless return, use a pass instead. This
fixes pylint R1711: "Useless return at end of function or method
(useless-return)".

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

scripts/west_commands/build.py

@@ -276,7 +276,7 @@ class Build(Forceable):
             if remainder:
                 self.args.cmake_opts = remainder
         except IndexError:
-            return
+            pass
 
     def _parse_test_item(self, test_item):
         found_test_metadata = False