staging: comedi: vmk80xx: rename vmk80xx_attach_common()

In comedi drivers typically *_attach_common() is used as the 'common'
part of the comedi_driver attach code for drivers that support various
bus types (ISA, PCI, etc.). This driver is specific to a USB device.

To avoid confusion when grepping, rename this function to something
more appropriate.

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>