Decouple BAR reading from pci device init, handle errors gracefully

Pcidev_init() now returns struct pci_device * instead of a BAR stored in
PCI config space. This allows for real error checking instead of having
exit(1) everywhere in pcidev.c.
Thanks to Niklas Söderlund for coming up with the original error
handling patch which was slightly modified and folded into this patch.
Move the declaration of struct pci_device in programmer.h before the
first user.

Corresponding to flashrom svn r1644.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/nicnatsemi.c b/nicnatsemi.c
index 60d8f87..d62a73f 100644
--- a/nicnatsemi.c
+++ b/nicnatsemi.c
@@ -52,22 +52,19 @@
 		.chip_writen		= fallback_chip_writen,
 };
 
-static int nicnatsemi_shutdown(void *data)
-{
-	pci_cleanup(pacc);
-	return 0;
-}
-
 int nicnatsemi_init(void)
 {
+	struct pci_dev *dev = NULL;
+
 	if (rget_io_perms())
 		return 1;
 
-	io_base_addr = pcidev_init(PCI_BASE_ADDRESS_0, nics_natsemi);
-
-	if (register_shutdown(nicnatsemi_shutdown, NULL))
+	dev = pcidev_init(nics_natsemi, PCI_BASE_ADDRESS_0);
+	if (!dev)
 		return 1;
 
+	io_base_addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+
 	/* The datasheet shows address lines MA0-MA16 in one place and MA0-MA15
 	 * in another. My NIC has MA16 connected to A16 on the boot ROM socket
 	 * so I'm assuming it is accessible. If not then next line wants to be