scsi: megaraid_sas: Rework code around controller reset

No functional change.  This patch reworks code around controller reset path
which gets rid of a couple of goto labels.  This is in preparation for the
next patch which adds PCI config space access locking while controller
reset is in progress.

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