Revert "Manta: Lets use prebuilt kernel"

This reverts commit 61953ae5a9e5f239132c0f0527442bb7896843a1.

Change-Id: I6cb540244da3c026140f6f1d93d61897d345e303
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>
Manta: Remove custom toolchaing

  * Lets disable this for now. At some point we can readd

Change-Id: I4678b5f5bf9db0e55d55a2f905c346a957c34263
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>