drivers/net: remove duplicate structure field initialization

The definitions of vnet_ops and ehea_netdev_ops have initializations of a
local function and eth_change_mtu for their respective ndo_change_mtu
fields.  This change uses only the local function.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier I, s, fld;
position p0,p;
expression E;
@@

struct I s =@p0 { ... .fld@p = E, ...};

@s@
identifier I, s, r.fld;
position r.p0,p;
expression E;
@@

struct I s =@p0 { ... .fld@p = E, ...};

@script:python@
p0 << r.p0;
fld << r.fld;
ps << s.p;
pr << r.p;
@@

if int(ps[0].line)!=int(pr[0].line) or int(ps[0].column)!=int(pr[0].column):
  cocci.print_main(fld,p0)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>