hpsa: fix allocation sizes for CISS_REPORT_LUNs commands

We were allocating roughly double the amount of memory
we should be due to ReportLUNdata and ExtendedReportLUNdata
containing a non-zero sized array but adding extra memory
to allocate as if the array were zero sized.

Track the logical and physical sizes separately.
Allocate the memory based on the specific data
structure sizes.

Signed-off-by: Don Brace <don.brace@pmcs.com>
Reviewed-by: Webb Scales <webb.scales@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>