bnxt_en: Add support for a new ethtool dump flag 3

bnxt_en: Add support for a new ethtool dump flag 3

When doing a live coredump with ethtool -w, the context data cached
in the NIC is not dumped by the FW by default.  The reason is that
retrieving this cached context data with traffic running may cause
problems.  Add a new dump flag 3 to allow the option to include this
cached context data which may be useful in some debug scenarios.

Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Damodharam Ammepalli <damodharam.ammepalli@broadcom.com>
Signed-off-by: Vasuthevan Maheswaran <vasuthevan.maheswaran@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250310183129.3154117-2-michael.chan@broadcom.com
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>