[PATCH] mm, kasan: Update kasan docs to indicate arm64 support

On Tue, 16 Aug 2016 09:30:31 -0700
Laura Abbott [off-list ref] wrote:

KASAN has been supported on arm64 since 39d114ddc682 ("arm64: add KASAN
support"). Update the docs to indicate this.

This creates a conflict with my patch sphinxifying this file, of course,
but I'll cope.  Applied to the docs tree, thanks.

jon