f2fs: make local functions static

Fixes the following sparse warnings:

fs/f2fs/segment.c:887:6: warning:
 symbol '__check_sit_bitmap' was not declared. Should it be static?
fs/f2fs/segment.c:1327:6: warning:
 symbol 'f2fs_wait_discard_bio' was not declared. Should it be static?
fs/f2fs/super.c:1661:5: warning:
 symbol 'f2fs_get_projid' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -884,7 +884,7 @@ static void f2fs_submit_discard_endio(struct bio *bio)
 	bio_put(bio);
 }
 
-void __check_sit_bitmap(struct f2fs_sb_info *sbi,
+static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
 				block_t start, block_t end)
 {
 #ifdef CONFIG_F2FS_CHECK_FS
@@ -1324,7 +1324,7 @@ static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
 }
 
 /* This should be covered by global mutex, &sit_i->sentry_lock */
-void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
+static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct discard_cmd *dc;

fs/f2fs/super.c

@@ -1691,7 +1691,7 @@ void f2fs_quota_off_umount(struct super_block *sb)
 		f2fs_quota_off(sb, type);
 }
 
-int f2fs_get_projid(struct inode *inode, kprojid_t *projid)
+static int f2fs_get_projid(struct inode *inode, kprojid_t *projid)
 {
 	*projid = F2FS_I(inode)->i_projid;
 	return 0;