rseq: Fix rseq unregistration regression

A logic inversion in rseq_reset_rseq_cpu_node_id() causes the rseq
unregistration to fail when rseq_validate_ro_fields() succeeds rather
than the opposite.

This affects both CONFIG_DEBUG_RSEQ=y and CONFIG_DEBUG_RSEQ=n.

Fixes: 7d5265f ("rseq: Validate read-only fields under DEBUG_RSEQ config")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250116205956.836074-1-mathieu.desnoyers@efficios.com

kernel/rseq.c

@@ -201,7 +201,7 @@ static int rseq_reset_rseq_cpu_node_id(struct task_struct *t)
 	/*
 	 * Validate read-only rseq fields.
 	 */
-	if (!rseq_validate_ro_fields(t))
+	if (rseq_validate_ro_fields(t))
 		return -EFAULT;
 	/*
 	 * Reset cpu_id_start to its initial state (0).