drivers/net/wireless/ti/wlcore/main.c: eliminate possible double power off

The function wl12xx_set_power_on is only called twice, once in
wl12xx_chip_wakeup and once in wl12xx_get_hw_info.  On the failure of the
call in wl12xx_chip_wakeup, the containing function just returns, but on
the failure of the call in wl12xx_get_hw_info, the containing function
calls wl1271_power_off.  This does not seem necessary, because if
wl12xx_set_power_on has set the power on and then fails, it has already
turned the power off.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/

)

// <smpl>
@r@
identifier f,free,a;
parameter list[n] ps;
type T;
expression e;
@@

f(ps,T a,...) {
  ... when any
      when != a = e
  if(...) { ... free(a); ... return ...; }
  ... when any
}

@@
identifier r.f,r.free;
expression x,a;
expression list[r.n] xs;
@@

* x = f(xs,a,...);
  if (...) { ... free(a); ... return ...; }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Luciano Coelho <luca@coelho.fi>