staging: kpc2000: simplify error handling in kp2000_pcie_probe

We can get rid of a few iounmaps in the middle of the function by
re-ordering the error handling labels and adding two new labels.

Signed-off-by: Simon Sandström <simon@nikanor.nu>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>