docs/driver-model: fix typo

No need to be be, just be should be sufficient.

Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt
index 1e70220..2403eb8 100644
--- a/Documentation/driver-model/device.txt
+++ b/Documentation/driver-model/device.txt
@@ -50,7 +50,7 @@
 Please see Documentation/filesystems/sysfs.txt for more information
 on how sysfs works.
 
-As explained in Documentation/kobject.txt, device attributes must be be
+As explained in Documentation/kobject.txt, device attributes must be
 created before the KOBJ_ADD uevent is generated. The only way to realize
 that is by defining an attribute group.