hv: vmbus: Constify struct kobj_type and struct attribute_group

vmbus_chan_group  and vmbus_chan_type are not modified. They are only
used in the helpers which take a const type parameter.

Constifying these structures and moving them to a read-only section can
increase over all security.

```
[Before]
   text   data    bss    dec    hex    filename
  20568   4699     48  25315   62e3    drivers/hv/vmbus_drv.o

[After]
   text   data    bss    dec    hex    filename
  20696   4571     48  25315   62e3    drivers/hv/vmbus_drv.o
```

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Naman Jain <namjain@linux.microsoft.com>
Link: https://lore.kernel.org/r/20240904011553.2010203-1-lihongbo22@huawei.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240904011553.2010203-1-lihongbo22@huawei.com>