megaraid_sas: Initialize tasklet before setting up IRQs

megaraid_sas: Initialize tasklet before setting up IRQs

Orabug: 22620626

It may happen (kdump), that an interrupt is invoked just after the
setup_irqs function was called but before the tasklet was initialised.
At this phase the hw ints should have been disabled, but for unknown
reason this mechanism seems to not work properly.

From: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit 91626c2701acad605c434b5e8245cbeea6671382)
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>