[SCSI] mpt2sas: Fix for max_sectors warning message is stating the incorrect range

When specifying the command line option "max_sectors" less than 64, then
warning message should provide correct upper boundary value 32767 instead of
8192.

Signed-off-by: Sreekanth Reddy <sreekanth.reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>