staging: comedi: daqboard2000: Remove function db2k_initialize_dac()

Remove function db2k_initialize_dac as all it does is call
db2k_dac_disarm.
Modify call site accordingly.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190725052359.2308-1-nishkadg.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>