wimax: fix typo in kernel-doc for debugfs_dentry in struct wimax_dev

The kernel-doc was referring to member @debufs_dentry instead of
@debugfs_dentry.

Reported by Randy Dunlap http://marc.info/?l=linux-netdev&m=123147942302885&w=2

As well, escape the colon in the field's text description, as it is
causing the generated text to be erraticly broken up (with paragraphs
moved down). Could not find a reason why it is happening so, even when
other field descriptions use colons and work as expected.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/wimax.h

@@ -323,8 +323,8 @@ struct input_dev;
  *
  * @rf_hw: [private] State of the hardware radio switch (OFF/ON)
  *
- * @debufs_dentry: [private] Used to hook up a debugfs entry. This
- *     shows up in the debugfs root as wimax:DEVICENAME.
+ * @debugfs_dentry: [private] Used to hook up a debugfs entry. This
+ *     shows up in the debugfs root as wimax\:DEVICENAME.
  *
  * Description:
  * This structure defines a common interface to access all WiMAX