libs2/tf: Fix a/z/c/z/z/s/l/z/T/cmock submodule to v2.5.3-g9d092898

Observed issue on ver_1.7.0-27-g1302b2a5 was:

    docker build https://github.com/SiliconLabsSoftware/z-wave-protocol-controller.git#main
    unable to prepare context: unable to 'git clone' to temporary context directory: \
      error initializing submodules: fatal: No url found for submodule path \
        'applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework/cmock' in .gitmodules

This was done using:

    git submodule add --force \
      https://github.com/throwtheswitch/cmock \
      applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework/cmock

     git -C applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework/cmock \
        checkout v2.5.3-g9d092898

Relate-to: #57 (comment)
Origin: #59
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework/cmock"]
+	path = applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework/cmock
+	url = https://github.com/throwtheswitch/cmock