megaraid_sas: use raw_smp_processor_id()

We only want to steer the I/O completion towards a queue, but don't
actually access any per-CPU data, so the raw_ version is fine to use
and avoids the warnings when using smp_processor_id().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Andy Lutomirski <luto@kernel.org>
Tested-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Sumit Saxena <sumit.saxena@avagotech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Odin.com>