xattr: add missing consts to function arguments

Add missing consts to xattr function arguments.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 6445b64..cdb14ad 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -93,7 +93,7 @@
 int security_sid_to_context(u32 sid, char **scontext,
 	u32 *scontext_len);
 
-int security_context_to_sid(char *scontext, u32 scontext_len,
+int security_context_to_sid(const char *scontext, u32 scontext_len,
 	u32 *out_sid);
 
 int security_context_to_sid_default(char *scontext, u32 scontext_len,