ARM64: tegra: remove *.mk files from kernel

ARM64: tegra: remove *.mk files from kernel

Remove BoardConfig.mk and CleanSpec.mk files from kernel as
required flag is already set from user space and no need
of keeping these files now in kernel

Bug 1456092

Change-Id: Ibf93ebdd4cb9107331854ad93dde8e9ad068d9e5
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/384834
(cherry picked from commit 52f8b206e58a5dd43fa4d8975dd68036d5825ee2)
Reviewed-on: http://git-master/r/385991
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sachin Nikam <snikam@nvidia.com>