staging:ced1401: remove read write callbacks from fops

As the driver says that read and writes should not be performed
and instead the user to kernel transactions are performed through
ioctl interface, remove these functions as they are not required

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>