smcf_unit_test: Create module unit tests
Created by: abhishek-arm
This patch added unit tests for SMCF(SMCF_MODULE, MGI, SMCF_DATA). The tests for mod_smcf.c requires mocking the mgi.c functions. The required mocks are generated using the mock generator script gm.rb in unit_test directory and saved under smcf/test/mocks directory.