BACKPORT: f2fs: check pinfile in gc_data_segment() in advance

In order to skip migrating section which contains data of pinned
file in advance.

Bug: 278486610
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Chao Yu <chao@kernel.org>
(cherry picked from commit 3c4b4e19)
Change-Id: Ia5d0fa83376afd60cb9dec1ef2e377fedfd905f5