staging: comedi: s626: remove unneeded local variable in attach_pci()

The 'result' variable is only used to check the return from
comedi_pci_enable(). Just reuse the 'ret' variable.

Also, remove the kernel noise and use the error code from
comedi_pci_enable() instead of returning -ENODEV.

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>