smb3: display debug information better for encryption

Fix /proc/fs/cifs/DebugData to use the same case for "encryption"
(ie "Encryption" with init capital letter was used in one place).
In addition, if gcm256 encryption (intead of gcm128) is used on
a connection to a server, note that in the DebugData as well.

It now displays (when gcm256 negotiated):
 Security type: RawNTLMSSP  SessionId: 0x86125800bc000b0d encrypted(gcm256)

Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>