drivers/net/wan: Remove redundant test

arg is checked not to be NULL a few lines before.

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>

drivers/net/wan/pc300_drv.c

@@ -2718,9 +2718,8 @@ static int cpc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 					}
 					pc300patrntst.num_errors =
 						falc_pattern_test_error(card, ch);
-					if (!arg
-					    || copy_to_user(arg, &pc300patrntst,
-							    sizeof (pc300patterntst_t)))
+					if (copy_to_user(arg, &pc300patrntst,
+							 sizeof(pc300patterntst_t)))
 							return -EINVAL;
 				} else {
 					falc_pattern_test(card, ch, pc300patrntst.patrntst_on);