[SCSI] megaraid_sas: new template defined to represent each type of controllers

This patch defines a new template to represent each type of
controllers (identified by the processor used). The template has
members that is set with appropriate values during driver
initialisation. This change is done to support new controllers with
minimal change to existing code. In future, for a new controller
support, a template will be declared and its members initialised
appropriately.

Signed-off-by: Sumant Patro <Sumant.Patro@lsil.com>

Rejections fixed and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>