smb311: correct incorrect offset field in compression header

[ Upstream commit 68c5818a ]

The offset field in the compression header is 32 bits not 16.

Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reported-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>