Remove framebuffer video drivers from ramdisks.

We now forcibly remove all framebuffer video drivers from ramdisks, as
part of our ongoing effort to keep every kernel we boot, in text mode,
so it can be more easily intercepted by LOM hardware, nova console
logging, etc.

Fixes-Bug: #1178409

Change-Id: Ia72211c97c03c3f60eb9a1483297fe587de51f0b
Merge "Remove framebuffer video drivers from ramdisks."