autofs: create autofs Kconfig and Makefile

Create Makefile and Kconfig for autofs module.

[raven@themaw.net: make autofs4 Kconfig depend on AUTOFS_FS]
  Link: http://lkml.kernel.org/r/152687649097.8263.7046086367407522029.stgit@pluto.themaw.net
Link: http://lkml.kernel.org/r/152626705591.28589.356365986974038383.stgit@pluto.themaw.net


Signed-off-by: Ian Kent <raven@themaw.net>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>