bnxt_en: Issue PCIe FLR in kdump kernel to cleanup pending DMAs.

If crashed kernel does not shutdown the NIC properly, PCIe FLR
is required in the kdump kernel in order to initialize all the
functions properly.

Fixes: d629522e ("bnxt_en: Reduce memory usage when running in kdump kernel.")
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>