ixgbe: use kzalloc for allocating one thing

Use kzalloc rather than kcalloc(1..

The semantic patch that makes this change is as follows:

// <smpl>
@@
@@

- kcalloc(1,
+ kzalloc(
          ...)
// </smpl>

and removing checkpatch below CHECK:
CHECK: Prefer kzalloc(sizeof(*fwd_adapter)...) over
kzalloc(sizeof(struct ixgbe_fwd_adapter)...)

Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>