ksmbd: return FILE_DEVICE_DISK instead of super magic

[ Upstream commit 25a6e135 ]

MS-SMB2 specification describes setting ->DeviceType to FILE_DEVICE_DISK
or FILE_DEVICE_CD_ROM. Set FILE_DEVICE_DISK instead of super magic in
FS_DEVICE_INFORMATION. And Set FILE_READ_ONLY_DEVICE for read-only share.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>