scsi: storvsc: Avoid allocating memory for temp cpumasks

Current code allocates 240 Kbytes (in typical configs) for each synthetic
SCSI controller to use as temp cpumask variables.  Recode to avoid needing
the temp cpumask variables and remove the memory allocation.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>