entry: Remove local_irq_{enable,disable}_exit_to_user()

entry: Remove local_irq_{enable,disable}_exit_to_user()

local_irq_enable_exit_to_user() and local_irq_disable_exit_to_user() are
never overridden by architecture code, and are always equivalent to
local_irq_enable() and local_irq_disable().

These functions were added on the assumption that arm64 would override
them to manage 'DAIF' exception masking, as described by Thomas Gleixner
in these threads:

  https://lore.kernel.org/all/20190919150809.340471236@linutronix.de/
  https://lore.kernel.org/all/alpine.DEB.2.21.1910240119090.1852@nanos.tec.linutronix.de/

In practice arm64 did not need to override either. Prior to moving to
the generic irqentry code, arm64's management of DAIF was reworked in
commit:

  97d935faacde ("arm64: Unmask Debug + SError in do_notify_resume()")

Since that commit, arm64 only masks interrupts during the 'prepare' step
when returning to user mode, and masks other DAIF exceptions later.
Within arm64_exit_to_user_mode(), the arm64 entry code is as follows:

	local_irq_disable();
	exit_to_user_mode_prepare_legacy(regs);
	local_daif_mask();
	mte_check_tfsr_exit();
	exit_to_user_mode();

Remove the unnecessary local_irq_enable_exit_to_user() and
local_irq_disable_exit_to_user() functions.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260407131650.3813777-3-mark.rutland@arm.com