src/device: Add check for existence and validity of PCIE base address config

Signed-off-by: Aamir Bohra <aamir.bohra@intel.com>
Change-Id: I89b0e9c927d395ac6d27201e0b3a8658e958518d
Reviewed-on: https://review.coreboot.org/27263
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/device/pci_ops_mmconf.c b/src/device/pci_ops_mmconf.c
index fb085a6..40fa632 100644
--- a/src/device/pci_ops_mmconf.c
+++ b/src/device/pci_ops_mmconf.c
@@ -17,6 +17,10 @@
 #include <device/pci_ids.h>
 #include <device/pci_ops.h>
 
+#if !defined(CONFIG_MMCONF_BASE_ADDRESS) || !CONFIG_MMCONF_BASE_ADDRESS
+#error "CONFIG_MMCONF_BASE_ADDRESS needs to be non-zero!"
+#endif
+
 /*
  * Functions for accessing PCI configuration space with mmconf accesses
  */