[SCSI] megaraid_sas: register 16 byte CDB capability

This patch properly registers the 16 byte command length capability of
the megaraid_sas controlled hardware with the scsi midlayer.  All
megaraid_sas hardware supports 16 byte CDB's.

Signed-off-by: Joshua Giles <joshua_giles@dell.com>
Signed-off-by: Sumant Patro <Sumant.Patro@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>