staging: comedi: drivers: replace init_timer by setup_timer

This patch replaces init_timer and 2 step initialization of function and
data by setup_timer to make the code  more concise.

The issue was discovered using the following coccinelle script:

@@
expression ds, e1, e2;
@@

-init_timer (&ds);
+setup_timer (&ds, e1, e2);
...
-ds.function = e1;
...
-ds.data = e2;

Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>