r6040: disable pci device if the subsequent calls (after pci_enable_device) fails

the calls after the pci_enable_device may fail, and will error out with out
disabling it. disable the device at error paths.

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>