Move global io_base_addr into compilation units

Corresponding to flashrom svn r1813.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/nic3com.c b/nic3com.c
index 27e28c7..145554d 100644
--- a/nic3com.c
+++ b/nic3com.c
@@ -33,6 +33,7 @@
 
 #define PCI_VENDOR_ID_3COM	0x10b7
 
+static uint32_t io_base_addr = 0;
 static uint32_t internal_conf;
 static uint16_t id;