ksmbd: set SMB2_SESSION_FLAG_ENCRYPT_DATA when enforcing data encryption for this share

[ Upstream commit 37ba7b00

 ]

Currently, SMB2_SESSION_FLAG_ENCRYPT_DATA is always set session setup
response. Since this forces data encryption from the client, there is a
problem that data is always encrypted regardless of the use of the cifs
seal mount option. SMB2_SESSION_FLAG_ENCRYPT_DATA should be set according
to KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION flags, and in case of
KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION_OFF, encryption mode is turned off for
all connections.

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