qcow2: Simplify size round-up in co_create_opts

Use the now-existing qcow2_opts pointer to simplify the size rounding up
code.

Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20250530084448.192369-3-hreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/qcow2.c

@@ -4150,8 +4150,7 @@ qcow2_co_create_opts(BlockDriver *drv, const char *filename, QemuOpts *opts,
     }
 
     /* Silently round up size */
-    create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size,
-                                            BDRV_SECTOR_SIZE);
+    qcow2_opts->size = ROUND_UP(qcow2_opts->size, BDRV_SECTOR_SIZE);
 
     /* Create the qcow2 image (format layer) */
     ret = qcow2_co_create(create_options, errp);