f2fs: remove several redundant assignments

There are several assignments to variables that are redundant
as the values are never read when the variables are updated later
and so the redundant statements can be safely removed.

Cleans up clang warnings:
fs/f2fs/segment.c:923:19: warning: Value stored to 'p' during its initialization is never read
fs/f2fs/segment.c:2060:2: warning: Value stored to 'hint' is never read
fs/f2fs/segment.c:2353:2: warning: Value stored to 'start_block' is never read
fs/f2fs/segment.c:2354:2: warning: Value stored to 'end_block' is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -958,7 +958,7 @@ static struct discard_cmd *__insert_discard_tree(struct f2fs_sb_info *sbi,
 				struct rb_node *insert_parent)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct rb_node **p = &dcc->root.rb_node;
+	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct discard_cmd *dc = NULL;
 
@@ -2095,7 +2095,6 @@ find_other_zone:
 	}
 	secno = left_start;
 skip_left:
-	hint = secno;
 	segno = GET_SEG_FROM_SEC(sbi, secno);
 	zoneno = GET_ZONE_FROM_SEC(sbi, secno);
 
@@ -2388,9 +2387,6 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
 						GET_SEGNO(sbi, end);
 
-	start_block = START_BLOCK(sbi, start_segno);
-	end_block = START_BLOCK(sbi, end_segno + 1);
-
 	cpc.reason = CP_DISCARD;
 	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));