Revert "Add /boot files as ramdisk_boot_file."

This reverts commit 2576a2fc30dd030292b65dfbaee0e0afb8b75ee7.

Reason for revert: conflict with device-specific sepolicy

Bug: 170411692
Change-Id: Ie5fde9dd91b603f155cee7a9d7ef432a05dc6827
Test: pass
6 files changed