[CIFS] ntlmv2/ntlmssp remove-unused-function CalcNTLMv2_partial_mac_key

This function is not used, so remove the definition and declaration.

Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>