x86/platform/uv/BAU: Add APIC idt entry

BAU uses the old alloc_initr_gate90 method to setup its interrupt. This
fails silently as the BAU vector is in the range of APIC vectors that are
registered to the spurious interrupt handler. As a consequence BAU
broadcasts are not handled, and the broadcast source CPU hangs.

Update BAU to use new idt structure.

Fixes: dc20b2d5

 ("x86/idt: Move interrupt gate initialization to IDT code")
Signed-off-by: Andrew Banman <abanman@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Cc: Russ Anderson <rja@hpe.com>
Cc: stable@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/1522188546-196177-1-git-send-email-abanman@hpe.com