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/satamv.c b/satamv.c
index b44e1cf..3065f0c 100644
--- a/satamv.c
+++ b/satamv.c
@@ -88,6 +88,9 @@
 		return 1;
 
 	addr = pcidev_readbar(dev, PCI_BASE_ADDRESS_0);
+	if (!addr)
+		return 1;
+
 	mv_bar = rphysmap("Marvell 88SX7042 registers", addr, 0x20000);
 	if (mv_bar == ERROR_PTR)
 		return 1;
@@ -136,6 +139,9 @@
 
 	/* Get I/O BAR location. */
 	tmp = pcidev_readbar(dev, PCI_BASE_ADDRESS_2);
+	if (!addr)
+		return 1;
+
 	/* Truncate to reachable range.
 	 * FIXME: Check if the I/O BAR is actually reachable.
 	 * This is an arch specific check.