acct.h: get rid of detritus

unused forward declarations of structs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/acct.h

@@ -19,9 +19,6 @@
 
 
 #ifdef CONFIG_BSD_PROCESS_ACCT
-struct vfsmount;
-struct super_block;
-struct pacct_struct;
 struct pid_namespace;
 extern int acct_parm[]; /* for sysctl */
 extern void acct_collect(long exitcode, int group_dead);