video: fbdev: wm8505fb use permission-specific DEVICE_ATTR variants

Use DEVICE_ATTR_RW for read-write attributes.  This simplifies the
source code, improves readbility, and reduces the chance of
inconsistencies.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@rw@
declarer name DEVICE_ATTR;
identifier x,x_show,x_store;
@@

DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);

@script:ocaml@
x << rw.x;
x_show << rw.x_show;
x_store << rw.x_store;
@@

if not (x^"_show" = x_show && x^"_store" = x_store)
then Coccilib.include_match false

@@
declarer name DEVICE_ATTR_RW;
identifier rw.x,rw.x_show,rw.x_store;
@@

- DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);
+ DEVICE_ATTR_RW(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/wm8505fb.c

@@ -182,7 +182,7 @@ static ssize_t contrast_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR(contrast, 0644, contrast_show, contrast_store);
+static DEVICE_ATTR_RW(contrast);
 
 static inline u_int chan_to_field(u_int chan, struct fb_bitfield *bf)
 {