cifsd: remove unneeded initialization of rc variable in ksmbd_crypt_message()

Remove unneeded initialization of rc variable in ksmbd_crypt_message().

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>