irqchip: or1k-pic: Undefine mask_ack for level triggered hardware

stable inclusion
from stable-v5.10.132
commit fd830d8dd59a8040a9c3009c8d6e175c3f23637c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YS3T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fd830d8dd59a8040a9c3009c8d6e175c3f23637c



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[ Upstream commit 85205013 ]

The mask_ack operation clears the interrupt by writing to the PICSR
register.  This we don't want for level triggered interrupt because
it does not actually clear the interrupt on the source hardware.

This was causing issues in qemu with multi core setups where
interrupts would continue to fire even though they had been cleared in
PICSR.

Just remove the mask_ack operation.

Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>