scsi: megaraid_sas: changes to function prototypes

Instead of the register address, pass the instance pointer to clear_intr
and read_fw_status_reg functions.  This is done in preparation for adding
adapter type based checks in these functions in later patches of this
series.

Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>