hvc: haven: Move CONSOLE_OPEN before hvc_instantiate

While calling hvc_instantiate, current log buffer is flushed through the
newly registered console driver. Presently, no call was made to
CONSOLE_OPEN, thus RM returns an error for all of these CONSOLE_WRITEs.
Move the CONSOLE_OPEN prior to calling hvc_instantiate.

Change-Id: Ia8d02f5cff819fee54ec66c4df140d0af216baa5
Signed-off-by: Elliot Berman <eberman@codeaurora.org>