bnxt_en: reinitialize IRQs when MTU is modified

bnxt_en: reinitialize IRQs when MTU is modified

MTU changes may affect the number of IRQs so we must call
bnxt_close_nic()/bnxt_open_nic() with the irq_re_init parameter
set to true.  The reason is that a larger MTU may require
aggregation rings not needed with smaller MTU.  We may not be
able to allocate the required number of aggregation rings and
so we reduce the number of channels which will change the number
of IRQs.  Without this patch, it may crash eventually in
pci_disable_msix() when the IRQs are not properly unwound.

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
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>