tf-m-build-and-test: Remove cs1k default config group

CS1K build config has been added into "pp_test" config group.
So "pp_corstone1000" config group can be deprecated.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: I9e782a49ff79f0e8a49573bfc5217d70e201c6d1
diff --git a/tf-m-build-and-test.yaml b/tf-m-build-and-test.yaml
index 3e901c8..6d8432f 100644
--- a/tf-m-build-and-test.yaml
+++ b/tf-m-build-and-test.yaml
@@ -24,8 +24,7 @@
     parameters:
       - string:
           name: 'FILTER_GROUP'
-          # TODO once available, use a group that filters to configurations we want
-          default: 'pp_test pp_corstone1000'
+          default: 'pp_test'
           description: |
             Filter to a group of configurations as recognised by configs.py
       - string: