securityfs: do not depend on CONFIG_SECURITY

Add a new Kconfig option SECURITYFS which will build securityfs support
but does not require CONFIG_SECURITY.  The only current user of
securityfs does not depend on CONFIG_SECURITY and there is no reason the
full LSM needs to be built to build this fs.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 3738cfa..f5fc64f 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -6,6 +6,7 @@
 	tristate "TPM Hardware Support"
 	depends on HAS_IOMEM
 	depends on EXPERIMENTAL
+	select SECURITYFS
 	---help---
 	  If you have a TPM security chip in your system, which
 	  implements the Trusted Computing Group's specification,