f2fs: don't set GC_FAILURE_PIN for background GC

stable inclusion
from stable-v5.10.137
commit d0311057395b6bc8eed0157dbd75157758f55a04
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d0311057395b6bc8eed0157dbd75157758f55a04



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[ Upstream commit 642c0969 ]

So that it can reduce the possibility that file be unpinned forcely by
foreground GC due to .i_gc_failures[GC_FAILURE_PIN] exceeds threshold.

Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>