CMake: Use 'patch' instead of 'git am'
CMake: Use 'patch' instead of 'git am'

Git invocations without an available gitconfig (ex. a test environment)
will fail whereas patch should always work. This adds a build dependecy on patch.

NervanaSystems/ngraph,NervanaSystems/ngraph,NervanaSystems/ngraph,NervanaSystems/ngraph