Documentation: update CodingStyle memory allocators

The list of available general purpose memory allocators in
Documentation/CodingStyle chapter 14 is incomplete. This patch adds
the missing vzalloc() to the list.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/CodingStyle

@@ -680,8 +680,8 @@ ones already enabled by DEBUG.
 		Chapter 14: Allocating memory
 
 The kernel provides the following general purpose memory allocators:
-kmalloc(), kzalloc(), kcalloc(), and vmalloc().  Please refer to the API
-documentation for further information about them.
+kmalloc(), kzalloc(), kcalloc(), vmalloc(), and vzalloc().  Please refer to
+the API documentation for further information about them.
 
 The preferred form for passing a size of a struct is the following: