HID: hid-appletb-bl: fix incorrect error message for default brightness

The error message responsible to show failure to set default backlight
brightness incorrectly showed the intended brightness as off irrespective
of what the user had set it. This patch intends to fix the same.

Also, a small typo in MODULE_DESCRIPTION has been fixed.

Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>