drivers/video/cg3.c: fix error return code

Author: Peter Senna Tschudin <peter.senna@gmail.com>

Convert a nonnegative error return code to a negative one, as returned
elsewhere in the function.

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

// 
(
if@p1 (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// 

Signed-off-by: Peter Senna Tschudin 
Signed-off-by: Florian Tobias Schandinat 

---
 drivers/video/cg3.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
 
diff --git a/drivers/video/cg3.c b/drivers/video/cg3.c
index f927a7b..c5e7612 100644
--- a/drivers/video/cg3.c
+++ b/drivers/video/cg3.c
@@ -398,7 +398,8 @@ static int __devinit cg3_probe(struct platform_device *op)
 			goto out_unmap_screen;
 	}
 
-	if (fb_alloc_cmap(&info->cmap, 256, 0))
+	err = fb_alloc_cmap(&info->cmap, 256, 0);
+	if (err)
 		goto out_unmap_screen;
 
 	fb_set_cmap(&info->cmap, info);