Staging: comedi: das08_cs.c: Checkpatch cleanup

ERROR: code indent should use tabs where possible
+        NONE$

ERROR: do not initialise statics to 0 or NULL
+static struct pcmcia_device *cur_dev = NULL;

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>