tty: Add Haven RM Console driver

Haven Resource Manager API defines a simple console for VM log sharing.
This patch adds support for this console with the HVC console framework.
It is possible to use this driver as the "primary VM" to listen to other
VM console logs or as the "secondary VM" to send logs to the "primary
VM". For the latter, CONFIG_HVC_HAVEN_CONSOLE must be set to y.

Change-Id: I3606b2d373535d0f347f66e5b729a303a9513fa8
Signed-off-by: Elliot Berman <eberman@codeaurora.org>