uapi: map_to_7segment: Update example in documentation

The device_attribute .show() and .store() methods gained an extra
parameter in v2.6.13, but the example in the documentation for the
7-segment header file was never updated.  Add the missing parameters.

While at it, get rid of the (misspelled) deprecated symbolic
permissions, and switch to DEVICE_ATTR_RW(), which was introduced in
v3.11

Fixes: 54b6f35c ("[PATCH] Driver core: change device_attribute callbacks")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20210207130543.2128980-1-geert@linux-m68k.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/map_to_7segment.h

@@ -45,17 +45,22 @@
  * In device drivers it is recommended, if required, to make the char map
  * accessible via the sysfs interface using the following scheme:
  *
- * static ssize_t show_map(struct device *dev, char *buf) {
+ * static ssize_t map_seg7_show(struct device *dev,
+ *				struct device_attribute *attr, char *buf)
+ * {
  *	memcpy(buf, &map_seg7, sizeof(map_seg7));
  *	return sizeof(map_seg7);
  * }
- * static ssize_t store_map(struct device *dev, const char *buf, size_t cnt) {
+ * static ssize_t map_seg7_store(struct device *dev,
+ *				 struct device_attribute *attr, const char *buf,
+ *				 size_t cnt)
+ * {
  *	if(cnt != sizeof(map_seg7))
  *		return -EINVAL;
  *	memcpy(&map_seg7, buf, cnt);
  *	return cnt;
  * }
- * static DEVICE_ATTR(map_seg7, PERMS_RW, show_map, store_map);
+ * static DEVICE_ATTR_RW(map_seg7);
  *
  * History:
  * 2005-05-31	RFC linux-kernel@vger.kernel.org