arch/um/drivers: remove duplicate structure field initialization

There are two initializations of ndo_set_mac_address, one to a local
function that is not used otherwise and one to a function that is defined
elsewhere.

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>

akpm:

- Use the standard eth_mac_addr() in uml_net_set_mac()

- Remove unneeded and racy local set_ether_mac()

- Remove duplicated (and incorrect)
  uml_netdev_ops.ndo_set_mac_address initializer.

Fixes 8bb95b39a16ed55226810596f92216c53329d2fe ("uml: convert network
device to netdevice ops").

[akpm@linux-foundation.org: rework as above]
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>