Disable Musca B1 from Travis and CircleCI

Musca B1's path has been renamed in TF-M so we need to update
`targets.json` in Mbed OS accordingly. As a CI-only branch, we
limit the scope to Musca S1 only.

Author: LDong-Arm

.circleci/config.yml

@@ -25,5 +25,6 @@ jobs:
           git clone --depth=1 --single-branch https://github.com/ARMmbed/mbed-os.git
       - compile:
           target: "ARM_MUSCA_S1"
-      - compile:
-          target: "ARM_MUSCA_B1"
+      # Temporarily disabled due to target rename in TF-M
+      # - compile:
+      #     target: "ARM_MUSCA_B1"

.travis.yml

@@ -84,6 +84,7 @@ matrix:
 
     # ARM_MUSCA_B1
 
-    - <<: *compile-tests
-      name: "Compile Regression and Compliance tests - ARM_MUSCA_B1"
-      env: TARGET_NAME=ARM_MUSCA_B1 CACHE_NAME=ARM_MUSCA_B1
+    # Temporarily disabled due to target rename in TF-M
+    # - <<: *compile-tests
+    #   name: "Compile Regression and Compliance tests - ARM_MUSCA_B1"
+    #   env: TARGET_NAME=ARM_MUSCA_B1 CACHE_NAME=ARM_MUSCA_B1