net/appletalk: Remove redundant test

atif is tested for being NULL twice, with the same effect in each case.  I
have kept the second test, as it seems to fit well with the comment above it.

A simplified version of the semantic patch that makes this change is as
follows: (http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
expression E;
position p1,p2;
@@

if (x@p1 == NULL || ...) { ... when forall
   return ...; }
... when != \(x=E\|x--\|x++\|--x\|++x\|x-=E\|x+=E\|x|=E\|x&=E\|&x\)
(
x@p2 == NULL
|
x@p2 != NULL
)

// another path to the test that is not through p1?
@s exists@
local idexpression r.x;
position r.p1,r.p2;
@@

... when != x@p1
(
x@p2 == NULL
|
x@p2 != NULL
)

@fix depends on !s@
position r.p1,r.p2;
expression x,E;
statement S1,S2;
@@

(
- if ((x@p2 != NULL) || ...)
  S1
|
- if ((x@p2 == NULL) && ...) S1
|
- BUG_ON(x@p2 == NULL);
)
// </smpl>

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

net/appletalk/ddp.c

@@ -815,9 +815,6 @@ static int atif_ioctl(int cmd, void __user *arg)
 				return -EPERM;
 			if (sa->sat_family != AF_APPLETALK)
 				return -EINVAL;
-			if (!atif)
-				return -EADDRNOTAVAIL;
-
 			/*
 			 * for now, we only support proxy AARP on ELAP;
 			 * we should be able to do it for LocalTalk, too.