bnxt_en: Fix RTNL lock usage on bnxt_get_port_module_status().

bnxt_get_port_module_status() calls bnxt_update_link() which expects
RTNL to be held.  In bnxt_sp_task() that does not hold RTNL, we need to
call it with a prior call to bnxt_rtnl_lock_sp() and the call needs to
be moved to the end of bnxt_sp_task().

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>