x86/platform/uv: Mark uv_bios_call() and uv_bios_call_irqsave() static

Both functions are only used inside of bios_uv.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Not-acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Russ Anderson <rja@hpe.com>
Link: https://lkml.kernel.org/r/20200504171527.2845224-2-hch@lst.de