hugetlbfs: add Kconfig help text

In kernel bugzilla #6248 (http://bugzilla.kernel.org/show_bug.cgi?id=6248),
Adrian Bunk <bunk@stusta.de> notes that CONFIG_HUGETLBFS is missing Kconfig
help text.
Signed-off-by: Arthur Othieno <apgo@patchbomb.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

fs/Kconfig

@@ -841,6 +841,12 @@ config TMPFS
 config HUGETLBFS
 	bool "HugeTLB file system support"
 	depends X86 || IA64 || PPC64 || SPARC64 || SUPERH || BROKEN
+	help
+	  hugetlbfs is a filesystem backing for HugeTLB pages, based on
+	  ramfs. For architectures that support it, say Y here and read
+	  <file:Documentation/vm/hugetlbpage.txt> for details.
+
+	  If unsure, say N.
 
 config HUGETLB_PAGE
 	def_bool HUGETLBFS