bcachefs: Fix an uninitialized field in bch_write_op

Regression from "bcachefs: Track incompressible data"
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/io.h

@@ -82,6 +82,7 @@ static inline void bch2_write_op_init(struct bch_write_op *op, struct bch_fs *c,
 	op->nr_replicas		= 0;
 	op->nr_replicas_required = c->opts.data_replicas_required;
 	op->alloc_reserve	= RESERVE_NONE;
+	op->incompressible	= 0;
 	op->open_buckets.nr	= 0;
 	op->devs_have.nr	= 0;
 	op->target		= 0;

fs/bcachefs/io_types.h

@@ -106,7 +106,7 @@ struct bch_write_op {
 	unsigned		compression_type:4;
 	unsigned		nr_replicas:4;
 	unsigned		nr_replicas_required:4;
-	unsigned		alloc_reserve:4;
+	unsigned		alloc_reserve:3;
 	unsigned		incompressible:1;
 
 	struct bch_devs_list	devs_have;