common: Move pci_init_board() out of common.h

This function can be dropped when all boards use driver model for PCI. For
now, move it into init.h with a comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 5db24f1..e8285bf 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -15,6 +15,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 
 #include <command.h>
 #include <env.h>