ext4: use true,false for bool variable

Fixes coccicheck warning:

fs/ext4/extents.c:5271:6-12: WARNING: Assignment of 0/1 to bool variable
fs/ext4/extents.c:5287:4-10: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1577241959-138695-1-git-send-email-zhengbin13@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/extents.c

@@ -5269,7 +5269,7 @@ ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
 {
 	int depth, err = 0;
 	struct ext4_extent *ex_start, *ex_last;
-	bool update = 0;
+	bool update = false;
 	depth = path->p_depth;
 
 	while (depth >= 0) {
@@ -5285,7 +5285,7 @@ ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
 				goto out;
 
 			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
-				update = 1;
+				update = true;
 
 			while (ex_start <= ex_last) {
 				if (SHIFT == SHIFT_LEFT) {