staging: ks7010: change name and type for device_open_status field

This commit changes type for device_open_status field of ks_wlan_private
structure from int to bool. This variable is only be set to 1
on ks_wlan_net_start and set to 0 on ks_wlan_net_stop. For this
purpose it is not necessary at all to use an integer because a bool
is enough. This also renames field name from device_open_status to
is_device_open.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>