UAPI: Fix AHZ multiple inclusion when __KERNEL__ is removed

Fix AHZ multiple inclusion when __KERNEL__ is removed as part of the separation
of the userspace headers from the kernel headers.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/include/linux/acct.h b/include/linux/acct.h
index 3e4737f..d537aa0 100644
--- a/include/linux/acct.h
+++ b/include/linux/acct.h
@@ -146,6 +146,9 @@
  *
  */
 
+#undef ACCT_VERSION
+#undef AHZ
+
 #ifdef CONFIG_BSD_PROCESS_ACCT_V3
 #define ACCT_VERSION	3
 #define AHZ		100