ANDROID: android-verity: Make it work with newer kernels

 Fixed bio API calls as they changed from 4.4 to 4.9.
 Fixed the driver to use the new verify_signature_one() API.
 Remove the dead code resulted from the rebase.

Bug: 72722987
Test: Build and boot hikey with system partition mounted as root using
      android-verity
Signed-off-by: Sandeep Patil <sspatil@google.com>

Change-Id: I1e29111d57b62f0451404c08d49145039dd00737