Revert half of "ANDROID: arm64: add vendor hooks for bti and pauth fault"

This reverts half of commit 06d07424.

The hooks android_rvh_do_bti is not used by any vendor, so remove them
to help with merge issues with future LTS releases.

If this is needed by any real user, it can easily be reverted to add it
back and then the symbol should be added to the abi list at the same
time to prevent it from being removed again later.

Bug: 203187389
Cc: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I840399ee4461c6bffa8c8b63d9cd5748d88d2aae