staging: comedi: contec_pci_dio: cleanup "find pci device" code

Add a couple local variables and reorder the tests to make
to make the more concise.

Change the printk to a dev_err when no match is found and reword
the message.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>