staging: gdm724x: remove ioctl call

This isn't needed, userspace can trigger off of the device id if they
need to do something "special" for different devices in special modes
depending on the device's endian issues.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Won Kang <wonkang@gctsemi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>