x86/platform/uv/BAU: Add wait_completion to bau_operations

Remove the present wait_completion routine and add a function pointer by
the same name to the bau_operations struct. Rather than switching on the
UV hub version during message processing, set the architecture-specific
uv*_wait_completion during initialization.

The uv123_bau_ops struct must be split into uv1 and uv2_3 versions to
accommodate the corresponding wait_completion routines.

Signed-off-by: Andrew Banman <abanman@hpe.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mike Travis <mike.travis@hpe.com>
Cc: sivanich@hpe.com
Cc: rja@hpe.com
Cc: akpm@linux-foundation.org
Link: http://lkml.kernel.org/r/1489077734-111753-6-git-send-email-abanman@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

