DocBook: fix various typos

This patch fixed spelling typo in various template files
within Documentation/Docbook.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/DocBook/usb.tmpl b/Documentation/DocBook/usb.tmpl
index 8d57c18..85fc0e2 100644
--- a/Documentation/DocBook/usb.tmpl
+++ b/Documentation/DocBook/usb.tmpl
@@ -153,7 +153,7 @@
 
 	<listitem><para>The Linux USB API supports synchronous calls for
 	control and bulk messages.
-	It also supports asynchnous calls for all kinds of data transfer,
+	It also supports asynchronous calls for all kinds of data transfer,
 	using request structures called "URBs" (USB Request Blocks).
 	</para></listitem>