staging: dgap: remove unneccessary dgap_init_pci() function

The dgap_init_pci() calls only pci_register_driver().
It doesn't need to make a function for that.

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>