cmdline: enable zcache

Change-Id: I4d0b9a268e2f23d55b904130e54579c30bea114a
Revert "m8: init: Configure interactive target up/down loads"

This was providing a small improvement but not enough to justify
diverging so much from everyone else.

Change-Id: I747ae0344e098760abf67f384a8deb65a3a42edd