block: Make BlockJobTypes const

Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/commit.c

@@ -173,7 +173,7 @@ static void commit_set_speed(BlockJob *job, int64_t speed, Error **errp)
     ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
 }
 
-static BlockJobType commit_job_type = {
+static const BlockJobType commit_job_type = {
     .instance_size = sizeof(CommitBlockJob),
     .job_type      = "commit",
     .set_speed     = commit_set_speed,

block/mirror.c

@@ -524,7 +524,7 @@ static void mirror_complete(BlockJob *job, Error **errp)
     block_job_resume(job);
 }
 
-static BlockJobType mirror_job_type = {
+static const BlockJobType mirror_job_type = {
     .instance_size = sizeof(MirrorBlockJob),
     .job_type      = "mirror",
     .set_speed     = mirror_set_speed,

block/stream.c

@@ -198,7 +198,7 @@ static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp)
     ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
 }
 
-static BlockJobType stream_job_type = {
+static const BlockJobType stream_job_type = {
     .instance_size = sizeof(StreamBlockJob),
     .job_type      = "stream",
     .set_speed     = stream_set_speed,