- Revert a commit to spinlock cleanup guards that got caught up
   in the subtle limitations & fragility of guards (again...) and
   caused a regression (Peter Zijlstra)

Signed-off-by: Ingo Molnar <mingo@kernel.org>

locking: Revert switching guards to _irq_{disable,enable}()

Revert commit 1b0866874833 ("locking: Switch to _irq_{disable,enable}()
variants in cleanup guards").

While the guards are properly nested, not all wrapped code is nice, as already
highlighted by that fair.c hunk.

Syzbot found another instance of this pattern in posix_timer_delete(), which
does spin_unlock_irq()+spin_lock_irq() inside scoped_guard(spinlock_irq).
Combined with this patch, that goes sideways most spectacular.

Undo this until we've developed stronger tools / debug for such issues.

Fixes: 1b0866874833 ("locking: Switch to _irq_{disable,enable}() variants in cleanup guards")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260824105523.GA4121620%40noisy.programming.kicks-ass.net