offb: Fix compile error on ppc32 systems

The code Ben H added needs <linux/pci.h> for things like pci_dev, etc.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

drivers/video/offb.c

@@ -26,6 +26,7 @@
 #include <linux/fb.h>
 #include <linux/init.h>
 #include <linux/ioport.h>
+#include <linux/pci.h>
 #include <asm/io.h>
 #include <asm/prom.h>