qed: fix kzalloc-simple.cocci warnings

drivers/net/ethernet/qlogic/qed/qed_dcbx.c:1230:13-20: WARNING: kzalloc should be used for dcbx_info, instead of kmalloc/memset
drivers/net/ethernet/qlogic/qed/qed_dcbx.c:1192:13-20: WARNING: kzalloc should be used for dcbx_info, instead of kmalloc/memset

 Use kzalloc rather than kmalloc followed by memset with 0

 This considers some simple cases that are common and easy to validate
 Note in particular that there are no ...s in the rule, so all of the
 matched code has to be contiguous

Generated by: scripts/coccinelle/api/alloc/kzalloc-simple.cocci

CC: Sudarsana Reddy Kalluru <sudarsana.kalluru@qlogic.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>