Add additional error handling to pcidev_readbar() callers

This is mostly a leftover of Niklas' "remove exit call from pcidev_init" patch.
While not explicitly necessary detecting errors early is usually a good idea.

Corresponding to flashrom svn r1718.

Signed-off-by: Niklas Söderlund <niso@kth.se>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/nicintel.c b/nicintel.c
index 305657c..98ba29f 100644
--- a/nicintel.c
+++ b/nicintel.c
@@ -76,12 +76,17 @@
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_2);
+	if (!addr)
+		return 1;
+
 	nicintel_bar = rphysmap("Intel NIC flash", addr, NICINTEL_MEMMAP_SIZE);
 	if (nicintel_bar == ERROR_PTR)
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
-	/* FIXME: This is not an aligned mapping. Use 4k? */
+	if (!addr)
+		return 1;
+
 	nicintel_control_bar = rphysmap("Intel NIC control/status reg", addr, NICINTEL_CONTROL_MEMMAP_SIZE);
 	if (nicintel_control_bar == ERROR_PTR)
 		return 1;