Add copyright notice for Makefile.
Add copyright notice for Makefile.

Change-Id: I23694b48bb8ebfd155b77ffedbb8a3188a0ec7e5

project-oak/hafnium-verification,project-oak/hafnium-verification,project-oak/hafnium-verification,project-oak/hafnium-verification,project-oak/hafnium-verification,project-oak/hafnium-verification,project-oak/hafnium-verification