staging: vt6655: device_get_pci_info remove unused pci_read_config_*

These values are read from pci but never used.

Removing variables byRevId, SubSystemID, SubVendorID and pci_cmd.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>