mpi3mr: Enable Diag Save for All Diagnostic Fault Cases

This patch ensures the driver sets the Diag Save bit for all
diagnostic fault conditions before issuing a Diagnostic Fault Reset.

The firmware now incorporates logic to manage snapdump saving
and requires the driver to always set the Diag Save bit to enable
this feature. This change supports improved diagnostic data
collection and fault handling.

Reviewed by: ssaxena, imp
Differential Revision: https://reviews.freebsd.org/D49750