Update ReadMe file for we use the binaries of boot sector directly instead of building it.
Update ReadMe file for we use the binaries of boot sector directly instead of building it.

git-svn-id: 5648d1bec6962b0a6d1d1b40eba8cf5cdb62da3d@9559 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2