Revert "Add a reference to ucounts for each cred"

This reverts commit b2c4d9a33c which is
commit 905ae01c4ae2ae3df05bb141801b1db4b7d83c61 upstream.

This commit should not have been applied to the 5.10.y stable tree, so
revert it.

Reported-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/r/87v93k4bl6.fsf@disp2133
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/exec.c

@@ -1347,10 +1347,6 @@ int begin_new_exec(struct linux_binprm * bprm)
 	WRITE_ONCE(me->self_exec_id, me->self_exec_id + 1);
 	flush_signal_handlers(me, 0);
 
-	retval = set_cred_ucounts(bprm->cred);
-	if (retval < 0)
-		goto out_unlock;
-
 	/*
 	 * install the new credentials for this executable
 	 */